Home / windows overview / How to find out the frequency of RAM. Types and characteristics of RAM Memory frequency spd what does it mean

How to find out the frequency of RAM. Types and characteristics of RAM Memory frequency spd what does it mean

21.10.2020 windows overview

In this study, we will try to find an answer to the following question - what is more important for achieving maximum computer performance, high frequency random access memory or her low timings. And two sets of RAM produced by Super Talent will help us with this. Let's see how the memory modules look externally, and what characteristics they have.

⇡Super Talent X58

The manufacturer dedicated this kit to the Intel X58 platform, as evidenced by the inscription on the sticker. However, several questions immediately arise here. As everyone is well aware, in order to achieve maximum performance on the Intel X58 platform, it is highly recommended to use the three-channel mode of RAM. Despite this, this Super Talent memory kit consists of only two modules. Of course, for orthodox system builders, this approach may cause bewilderment, but there is still a rational grain in this. The fact is that the segment of top platforms is relatively small, and most personal computers use RAM in dual-channel mode. In this regard, the purchase of a set of three memory modules may seem unjustified to the average user, and if you really need a lot of RAM, you can purchase three sets of two modules each. The manufacturer indicates that the Super Talent WA1600UB2G6 memory can operate at 1600 MHz DDR with 6-7-6-18 timings. Now let's see what information is stored in the SPD profile of these modules.

And again there is some discrepancy between the real and declared characteristics. The maximum JEDEC profile assumes the operation of modules at a frequency of 1333 MHz DDR with timings of 9-9-9-24. However, there is an extended XMP profile, the frequency of which coincides with the declared one - 800 MHz (1600 MHz DDR), but the timings are somewhat different, and for the worse - 6-8-6-20, instead of 6-7-6-18, which are indicated on the sticker. Nevertheless, this set of RAM worked without problems in the declared mode - 1600 MHz DDR with timings of 6-7-6-18 and a voltage of 1.65 V. As for overclocking, higher frequencies were not obeyed by the modules, despite the installation of increased timings and increase the supply voltage. Moreover, when the voltage Vmem was increased to the level of 1.9 V, instability was observed in the initial mode as well. Unfortunately, the heatsinks are very firmly glued to the memory chips, so we did not dare to remove them for fear of damaging the memory modules. It's a pity, the type of chips used could shed light on this behavior of the modules.

⇡Super Talent P55

The second set of RAM, which we will consider today, is positioned by the manufacturer as a solution for Intel platforms P55. The modules are equipped with low-profile black heatsinks. The maximum declared mode assumes the operation of these modules at a frequency of 2000 MHz DDR with timings of 9-9-9-24 and a voltage of 1.65 V. Now let's look at the profiles wired into the SPD.

The most productive JEDEC profile assumes the operation of modules at a frequency of 800 MHz (1600 MHz DDR) with timings of 9-9-9-24 and a voltage of 1.5 V, and XMP profiles in this case missing. As for overclocking, with a slight increase in timings, these memory modules were able to operate at a frequency of 2400 MHz DDR, as evidenced by the screenshot below.

Moreover, the system booted even at 2600 MHz DDR, but the launch of test applications led to a hang or reboot. As in the case with the previous Super Talent memory kit, these modules did not react in any way to an increase in supply voltage. As it turned out, better overclocking memory and system stability were more facilitated by an increase in the voltage of the memory controller built into the processor. However, the search for the maximum possible frequencies and parameters at which stability is achieved in such extreme modes, we leave to enthusiasts. Next, we will focus on studying the next question - to what extent the frequency of RAM and its timings affect the overall performance of the computer. In particular, we will try to figure out what is better - to install high-speed RAM that works with high timings, or it is preferable to use the lowest possible timings, albeit not at maximum operating frequencies.

⇡ Test conditions

Testing was carried out on a stand with the following configuration. In all tests, the processor was running at 3.2 GHz, the reasons for this will be explained below, and a powerful graphics card was required for tests in the game Crysis.

As mentioned above, we will try to find out how the frequency of RAM and its timings affect the overall performance of the computer. Of course, these parameters can simply be set in the BIOS and tested. But, as it turned out, with a Bclk frequency of 133 MHz, the operating frequency range of the RAM in the motherboard we used is 800 - 1600 MHz DDR. This is not enough, because one of the Super Talent memory kits reviewed today supports DDR3-2000 mode. And in general, more and more high-speed memory modules are being produced, manufacturers assure us of their unprecedented performance, so it will definitely not hurt to find out their real performance. In order to set the memory frequency to, say, 2000 MHz DDR, it is necessary to increase the frequency of the Bclk bus. However, this will change the frequencies of both the processor core and its third-level cache, which operates at the same frequency as the QPI bus. Of course, it is incorrect to compare the results obtained under such different conditions. In addition, the degree of influence of the CPU frequency on the test results may turn out to be much more significant than the timings and frequency of the RAM. The question arises - is it possible to somehow get around this problem? As for the processor frequency, within certain limits it can be changed using a multiplier. However, it is desirable to choose a bclk frequency value such that the final RAM frequency is equal to one of the standard values ​​1333, 1600 or 2000. As you know, the base bclk frequency in Intel Nehalem processors is currently 133.3 MHz. Let's see what the frequency of the RAM will be at different values ​​of the bclk bus frequency, taking into account the multipliers that the motherboard we use can set. The results are shown in the table below.

Frequency bclk, MHz
133.(3) 150 166.(6) 183.(3) 200
Memory multiplier RAM frequency, MHz DDR
6 800 900 1000 1100 1200
8 1066 1200 1333 1466 1600
10 1333 1500 1667 1833 2000
12 1600 1800 2000 2200 2400

As can be seen from the table, with a bclk frequency of 166 MHz, frequencies of 1333 and 2000 MHz can be obtained for RAM. If the bclk frequency is 200 MHz, then we get the coincidence of the RAM frequencies at 1600 MHz, as well as the required 2000 MHz. In other cases, there are no coincidences with the standard memory frequencies. So which bclk frequency do you prefer in the end - 166 or 200 MHz? The following table will help answer this question. Here are the CPU frequency values, depending on the multiplier and the bclk frequency. To evaluate the impact of timings, we need not only the same memory frequencies, but also the CPU, so that this does not affect the results.

Frequency bclk, MHz
CPU multiplier 133.(3) 150.0 166.(6) 183.(3) 200.0
9 1200 1350 1500 1647 1800
10 1333 1500 1667 1830 2000
11 1467 1650 1833 2013 2200
12 1600 1800 2000 2196 2400
13 1733 1950 2167 2379 2600
14 1867 2100 2333 2562 2800
15 2000 2250 2500 2745 3000
16 2133 2400 2667 2928 3200
17 2267 2550 2833 3111 3400
18 2400 2700 3000 3294 3600
19 2533 2850 3167 3477 3800
20 2667 3000 3333 3660 4000
21 2800 3150 3500 3843 4200
22 2933 3300 3667 4026 4400
23 3067 3450 3833 4209 4600
24 3200 3600 4000 4392 4800

As a starting point, we took the maximum processor frequency (3200 MHz) that it can show with a bclk base frequency of 133 MHz. It can be seen from the table that under these conditions, only with a frequency of bclk=200 MHz, exactly the same CPU frequency can be obtained. The remaining frequencies, although close to 3200 MHz, are not exactly equal to it. Of course, the CPU frequency could be taken as the initial one, and even lower, say - 2000 MHz, then it would be possible to get correct results with all three values ​​of the bclk bus - 133, 166 and 200 MHz. However, we have abandoned this option. And that's why. First, desktop Intel processors there is no such frequency with the Nehalem architecture, and they are unlikely to appear. Secondly, lowering the CPU frequency by more than 1.5 times can lead to the fact that it becomes a limiting factor, and the difference in results will practically not depend on the mode of operation of the RAM. Actually, the first estimates showed exactly this. Thirdly, it is unlikely that the user who buys a deliberately weak and cheap processor will be very concerned about choosing an expensive high-speed RAM. So, we will test with base frequency bclk - 133 and 200 MHz. The CPU frequency in both cases is the same and equals 3200 MHz. Below are screenshots of the CPU-Z utility in these modes.

If you paid attention, the QPI-Link frequency depends on the bclk frequency and, accordingly, they differ by 1.5 times. By the way, this will allow us to find out how the L3 cache frequency in Nehalem processors affects the overall performance. So, let's start testing.

RAM FAQ

​

RAM - (RAM random access memory device) - is designed for temporary storage of data and commands necessary for the Central Processing Unit to perform operations. RAM transmits commands and data to the processor directly or through cache memory. Each RAM cell has its own address...

The most common types of memory are:


  • ^ SDR SDRAM(designations PC66, PC100, PC133)

  • DDR SDRAM(designations PC266, PC333, etc. or PC2100, PC2700)

  • RDRAM(PC800)

​

Now for further explanations, I will talk about timings and frequencies. Timing- this is the delay between the individual operations performed by the controller when accessing the memory.

If we consider the composition of memory, we get: its entire space is represented as cells (rectangles), which consist of a certain number of rows and columns. One such "rectangle" is called a page, and the collection of pages is called a bank.

To access a cell, the controller sets the bank number, page number in it, row number and column number, all requests take time, in addition, a rather large cost is spent on opening and closing the bank after the read / write operation itself. Each action takes time, it is called timing.

Now let's take a closer look at each of the timings. Some of them are not available for setting - access time CS# (crystal select) this signal determines the crystal (chip) on the module for the operation.

In addition, the rest can be changed:


  • ^RCD (RAS-to-CAS Delay) is the delay between signals RAS (Row Address Strobe) and CAS (Column Address Strobe), this parameter characterizes the interval between accesses to the bus by the signal memory controller RAS# and CAS#.

  • CAS Latency (CL) is the delay between the read command and the first word being readable. Introduced for a set of address registers guaranteed stable signal level.

  • ^RAS Precharge (RP) this is the re-issuance time (charge accumulation period) of the signal RAS#- after what time the memory controller will be able to issue a line address initialization signal again.
Note: the order of operations is exactly this (RCD-CL-RP), but often the timings are recorded not in order, but by "importance" - CL-RCD-RP.

  • ^ Precharge Delay(or Active Precharge Delay; more commonly referred to as Tras) is the time the row was active. Those. the period during which the row is closed if the next required cell is in another row.

  • ^ SDRAM Idle Timer(or SDRAM Idle Cycle Limit) the number of ticks the page stays open, after which the page is forced to close, either to access another page or to refresh (refresh)

  • ^ Burst Length this is a parameter that sets the size of the memory prefetch relative to the starting address of the access. The larger its size, the higher the memory performance.

Well, it seems that we figured out the basic concepts of timings, now let's take a closer look at memory ratings (PC100, PC2100, DDR333, etc.)

There are two types of designations for the same memory, one for the "effective frequency" of DDRxxx, and the second for the theoretical bandwidth of PCxxxx.

The designation "DDRxxx" has historically developed from the sequence of names of the standards "PC66-PC100-PC133" - when it was customary to associate the memory speed with the frequency (except that a new abbreviation "DDR" was introduced to distinguish SDR SDRAM from DDR SDRAM). Simultaneously with DDR SDRAM memory, RDRAM (Rambus) memory appeared, on which cunning marketers decided to set not the frequency, but the bandwidth - PC800. At the same time, the width of the data bus remained the same as it was 64 bits (8 bytes), that is, the same PC800 (800 MB / s) were obtained by multiplying 100 MHz by 8. Naturally, nothing has changed from the name, and PC800 RDRAM - the essence is the same the most PC100 SDRAM, only in a different package... This is nothing more than a sales strategy, roughly speaking, "to prick people". In response, the companies that produce modules began to write the theoretical throughput - PCxxxx. This is how PC1600, PC2100 and the next ones appeared... At the same time, DDR SDRAM has an effective frequency twice as high, which means more numbers on the designations.

Here is an example of matching notation:


  • 100MHz = PC1600 DDR SDRAM = DDR200 SDRAM = PC100 SDRAM = PC800 RDRAM

  • 133MHz = PC2100 DDR SDRAM = DDR266 SDRAM = PC133 SDRAM = PC1066 RDRAM

  • 166MHz = PC2700 DDR SDRAM = DDR333 SDRAM = PC166 SDRAM = PC1333 RDRAM

  • 200 MHz = PC3200 DDR SDRAM = DDR400 SDRAM = PC200 SDRAM = PC1600 RDRAM

  • 250 MHz = PC4000 DDR SDRAM = DDR500 SDRAM

As for ^RAMBUS (RDRAM) I will not write much, but I will try to present it to you.

There are three varieties of RDRAM - Base, Concurrent and direct. Base and Concurrent are almost the same thing, but Direct has decent differences, so I’ll talk about the first two in general, and about the last one in more detail.

^ Base RDRAM and Concurrent RDRAM basically differ only in operating frequencies: for the first, the frequency is 250-300 MHz, and for the second, this parameter, respectively, is 300-350 MHz. Data is transmitted at two data packets per clock, so that the effective transmission rate is twice as high. The memory uses an eight-bit data bus, which therefore gives a throughput of 500-600 Mb/s (BRDRAM) and 600-700 Mb/s (CRDRAM).

^Direct RDRAM (DRDRAM) unlike Base and Concurrent, it has a 16-bit bus and operates at a frequency of 400 MHz. The bandwidth of Direct RDRAM is 1.6 Gb/s (taking into account bidirectional data transfer), which already looks pretty good compared to SDRAM (1 Gb/s for PC133). Usually, when talking about RDRAM, they mean DRDRAM, so the letter "D" in the name is often omitted. When this type of memory appeared, Intel created a chipset for the Pentium 4 - the i850.

The biggest plus Rambus memory is that the more modules - the greater the bandwidth, for example, up to 1.6 Gb / s per channel and up to 6.4 Gb / s with four channels.

There are also two disadvantages, quite significant:

1. The paws are golden, and become unusable if the memory board is pulled out and inserted into the slot more than 10 times (approximately).

2. Overpriced, but many find very good use of this memory and are willing to pay big money for them.

That, perhaps, is all, we figured out the timings, names and denominations, now I will tell you a little about various important little things.

You probably saw the By SPD option in the BIOS "e when setting the memory frequency, what does this mean? ^SPD - Serial Presence Detect, this is a microcircuit on the module, in which all the parameters for the operation of the module are wired, these are the "default values" so to speak. Now, due to the appearance of "noname" companies, they began to write the name of the manufacturer and the date into this chip.

^ Register memory

Registered Memory it is a memory with registers that serve as a buffer between the memory controller and the module chips. Registers reduce the load on the synchronization system and allow you to collect a very large amount of memory (16 or 24 gigabytes) without overloading the controller circuits.

But this scheme has a drawback - the registers introduce a delay of 1 cycle for each operation, which means - register memory slower than normal, other things being equal. That is - the overclocker is not interested (and it is very expensive).

Everyone is now shouting about Dual channel - what is it?

^Dual channel- dual channel, this allows you to access two modules at the same time. Dual channel is not a type of modules, but a function integrated into motherboard. Can be used with two (preferably) identical modules. It turns on automatically when there are 2 modules.

Note: To activate this feature, you need to install modules in slots of different colors.

Parity and ECC

Memory with Parity it is a parity-checked memory capable of detecting some types of errors.

^ Memory with ECC This is an error-correcting memory that allows you to find and also correct the error of one bit in a byte. Used mainly on servers.

Note: it is slower than usual, not suitable for people who love speed.

^ What is DDR SDRAM :

DDR (Double Data Rate) memory provides data transfer over the memory-to-chipset bus twice per clock, on both edges of the clock signal. Thus, when working system bus and memory at the same clock frequency, the memory bus bandwidth is twice that of conventional SDRAM.

Two parameters are usually used in the designation of DDR memory modules: either the operating frequency (equal to twice the clock frequency) - for example, the clock frequency of the DR-400 memory is 200 MHz; or peak throughput (in Mb/s). The same DR-400 has a bandwidth of approximately 3200 Mb / s, so it can be referred to as PC3200. At present, DDR memory has lost its relevance and in new systems it has been almost completely superseded by the more modern DDR2. however, in order to keep afloat a large number of older computers that have DDR memory installed, it is still being released. The most common 184-pin DDR modules are PC3200 and, to a lesser extent, PC2700. DDR SDRAM may have Registered and ECC variants.

^ What is DDR2 memory :

DDR2 memory is the successor to DDR and is currently the dominant memory type for desktops, servers, and workstations. DDR2 is designed to operate at higher frequencies than DDR, is characterized by lower power consumption, as well as a set of new features (prefetch 4 bits per clock, built-in termination). In addition, unlike DDR chips, which were produced both in TSOP and FBGA packages, DDR2 chips are produced only in FBGA packages (which provides them with greater stability at high frequencies). DDR and DDR2 memory modules are not only electrically and mechanically compatible with each other: 240-pin brackets are used for DDR2, while 184-pin brackets are used for DDR. Today, the most common memory operating at a frequency of 333 MHz and 400 MHz, and referred to as DDR2-667 (PC2-5400/5300) and DDR2-800 (PC2-6400), respectively.

​

^ What is DDR3 memory :

The third generation DDR memory - DDR3 SDRAM will soon replace the current DDR2. The performance of the new memory has doubled compared to the previous one: now each read or write operation means access to eight groups of DDR3 DRAM data, which, in turn, using two different reference oscillators, are multiplexed over the I / O pins at a frequency of four times the clock frequency. Theoretically, effective DDR3 frequencies will be in the range of 800 MHz - 1600 MHz (at clock frequencies of 400 MHz - 800 MHz), thus, the marking of DDR3 depending on the speed will be: DDR3-800, DDR3-1066, DDR3-1333, DDR3-1600 . Among the main advantages of the new standard, first of all, it is worth noting significantly lower power consumption (supply voltage DDR3 - 1.5 V, DDR2 - 1.8 V, DDR - 2.5 V).

The downside of DDR3 against DDR2 (and, moreover, in comparison with DDR) is a large latency. Desktop DDR3 DIMMs will have the 240-pin structure we're familiar with from DDR2; however, there will be no physical compatibility between them (due to the "mirror" pinout and the different arrangement of the connector keys).

^ What is ECC memory :

ECC (Error Correct Code - error detection and correction) is used to correct random memory errors caused by various external factors, and is an improved version of the "parity check" system. Physically, ECC is implemented as an additional 8-bit memory chip installed next to the main ones. Thus, ECC modules are 72-bit (as opposed to standard 64-bit modules). Some types of memory (Registered, Full Buffered) are available only in ECC version.

^ What is Registered Memory :

Registered (registered) memory modules are mainly used in servers that work with large amounts of RAM. All of them have ECC, i.e. are 72-bit and, in addition, contain additional register chips for partial (or full - such modules are called Full Buffered, or FB-DIMM) data buffering, thereby reducing the load on the memory controller. Buffered DIMMs are generally incompatible with non-buffered ones.

^ What is SPD:

Any DIMM memory module has a small SPD (Serial Presence Detect) chip, in which the manufacturer records information about the operating frequencies and the corresponding delays of the memory chips necessary to ensure the normal operation of the module. Information from the SPD is read by the BIOS during the self-test phase of the computer before booting operating system and allows you to automatically optimize memory access parameters.
Types / types of RAM modules

​

There are quite a few types of random access memory (RAM). This article describes their characteristics so that you can have an idea of ​​\u200b\u200bdifferent RAM, because. not everyone is able to distinguish between types of RAM ...

FPM (Fast Page Mode) is a type of dynamic memory. Its name corresponds to the principle of operation, since the module allows you to quickly access data that is on the same page as the data transferred during the previous cycle. These modules were used in most 486-based computers and early Pentium-based systems circa 1995.

​

EDO (Extended Data Out) modules appeared in 1995 as a new type of memory for computers with Pentium processors. This is a modified version of FPM. Unlike its predecessors, EDO starts fetching the next block of memory at the same time it sends the previous block to the CPU.

SDRAM (Synchronous DRAM) is a type of random access memory that is fast enough to be synchronized with the processor speed, excluding standby modes. The microcircuits are divided into two blocks of cells so that when a bit in one block is accessed, preparations are made for accessing a bit in another block. If the access time for the first piece of information was 60 ns, all subsequent intervals could be reduced to 10 ns. Starting in 1996, most Intel chipsets began to support this type of memory module, making it very popular until 2001.

SDRAM can run at 133 MHz, which is almost three times faster than FPM and twice as fast as EDO. Most computers with Pentium and Celeron processors released in 1999 used this type of memory.

​

DDR (Double Data Rate) was the evolution of SDRAM. This kind of memory modules first appeared on the market in 2001. The main difference between DDR and SDRAM is that instead of doubling the clock speed to speed things up, these modules transfer data twice in one clock cycle. Now this is the main memory standard, but it is already starting to give way to DDR2.

​

DDR2 (Double Data Rate 2) is a newer version of DDR that should theoretically be twice as fast. DDR2 memory first appeared in 2003, and chipsets that support it - in mid-2004. This memory, like DDR, transfers two data sets per clock. The main difference between DDR2 and DDR is the ability to operate at significantly higher clock speeds due to design improvements. But the modified scheme of operation, which allows achieving high clock frequencies, at the same time increases the delays when working with memory.

​

^ RAMBUS (RIMM)

RAMBUS (RIMM) is a type of memory that entered the market in 1999. It is based on traditional DRAM but with a radically changed architecture. The RAMBUS design makes memory access more "intelligent", allowing data to be pre-accessed while offloading the CPU a bit. The basic idea used in these memory modules is to receive data in small bursts but at a very high clock rate. For example, SDRAM can transfer 64 bits of information at 100 MHz, while RAMBUS can transfer 16 bits at 800 MHz. These modules did not become successful as Intel had many problems implementing them. RDRAM modules appeared in the Sony Playstation 2 and Nintendo 64 game consoles.

Memory: RAM, DDR SDRAM, SDR SDRAM, PC100, DDR333, PC3200... how to figure it all out? Let's try!

So, the first thing we need to do is "smooth out" all the doubts and questions about the denominations in memory...

The most common types of memory are:

  • SDR SDRAM(designations PC66, PC100, PC133)
  • DDR SDRAM(designations PC266, PC333, etc. or PC2100, PC2700)
  • RDRAM(PC800)

Now for further explanations, I will talk about timings and frequencies. Timing- this is the delay between the individual operations performed by the controller when accessing the memory.

If we consider the composition of memory, we get: its entire space is represented as cells (rectangles), which consist of a certain number of rows and columns. One such "rectangle" is called a page, and the collection of pages is called a bank.

To access a cell, the controller sets the bank number, page number in it, row number and column number, all requests take time, in addition, a rather large cost is spent on opening and closing the bank after the read / write operation itself. Each action takes time, it is called timing.

Now let's take a closer look at each of the timings. Some of them are not available for configuration - access time CS# (crystal select) this signal determines the crystal (chip) on the module for the operation.

In addition, the rest can be changed:

  • RCD (RAS-to-CAS Delay) is the delay between signals RAS (Row Address Strobe) and CAS (Column Address Strobe), this parameter characterizes the interval between accesses to the bus by the signal memory controller RAS# and CAS#.
  • CAS Latency (CL) is the delay between the read command and the first word being readable. Introduced for a set of address registers guaranteed stable signal level.
  • RAS Precharge (RP) this is the re-issuance time (charge accumulation period) of the RAS # signal - after what time the memory controller will be able to issue the line address initialization signal again.

    • Note: the order of operations is exactly this (RCD-CL-RP), but often the timings are recorded not in order, but by "importance" - CL-RCD-RP.

  • Precharge Delay(or Active Precharge Delay; more commonly referred to as Tras) is the time the row was active. Those. the period during which the row is closed if the next required cell is in another row.
  • SDRAM Idle Timer(or SDRAM Idle Cycle Limit) the number of ticks the page stays open, after which the page is forced to close, either to access another page or to refresh (refresh)
  • burst length this is a parameter that sets the size of the memory prefetch relative to the starting address of the access. The larger its size, the higher the memory performance.

Well, it seems that we figured out the basic concepts of timings, now let's take a closer look at memory ratings (PC100, PC2100, DDR333, etc.)

There are two types of designations for the same memory, one for the "effective frequency" of DDRxxx, and the second for the theoretical bandwidth of PCxxxx.

The designation "DDRxxx" has historically developed from the sequence of names of the standards "PC66-PC100-PC133" - when it was customary to associate the memory speed with the frequency (except that a new abbreviation "DDR" was introduced to distinguish SDR SDRAM from DDR SDRAM). Simultaneously with DDR SDRAM memory, RDRAM (Rambus) memory appeared, on which cunning marketers decided to set not the frequency, but the bandwidth - PC800. At the same time, the width of the data bus remained the same as it was 64 bits (8 bytes), that is, the same PC800 (800 MB / s) were obtained by multiplying 100 MHz by 8. Naturally, nothing has changed from the name, and PC800 RDRAM - the essence is the same the most PC100 SDRAM, only in a different package... This is nothing more than a sales strategy, roughly speaking, "to prick people". In response, the companies that produce modules began to write the theoretical throughput - PCxxxx. This is how PC1600, PC2100 and the next ones appeared... At the same time, DDR SDRAM has an effective frequency twice as high, which means more numbers on the designations.

Here is an example of matching notation:

  • 100MHz = PC1600 DDR SDRAM = DDR200 SDRAM = PC100 SDRAM = PC800 RDRAM
  • 133MHz = PC2100 DDR SDRAM = DDR266 SDRAM = PC133 SDRAM = PC1066 RDRAM
  • 166MHz = PC2700 DDR SDRAM = DDR333 SDRAM = PC166 SDRAM = PC1333 RDRAM
  • 200 MHz = PC3200 DDR SDRAM = DDR400 SDRAM = PC200 SDRAM = PC1600 RDRAM
  • 250 MHz = PC4000 DDR SDRAM = DDR500 SDRAM

As for RAMBUS (RDRAM) I will not write much, but I will try to present it to you.

There are three varieties of RDRAM - Base, Concurrent and direct. Base and Concurrent are almost the same thing, but Direct has decent differences, so I’ll talk about the first two in general, and about the last one in more detail.

Base RDRAM and Concurrent RDRAM basically differ only in operating frequencies: for the first, the frequency is 250-300 MHz, and for the second, this parameter, respectively, is 300-350 MHz. Data is transmitted at two data packets per clock, so that the effective transmission rate is twice as high. The memory uses an eight-bit data bus, which therefore gives a throughput of 500-600 Mb/s (BRDRAM) and 600-700 Mb/s (CRDRAM).

Direct RDRAM (DRDRAM) unlike Base and Concurrent, it has a 16-bit bus and operates at a frequency of 400 MHz. The bandwidth of Direct RDRAM is 1.6 Gb/s (taking into account bidirectional data transfer), which already looks pretty good compared to SDRAM (1 Gb/s for PC133). Usually, when talking about RDRAM, they mean DRDRAM, so the letter "D" in the name is often omitted. When this type of memory appeared, Intel created a chipset for the Pentium 4 - the i850.

The biggest plus Rambus memory is that the more modules - the greater the bandwidth, for example, up to 1.6 Gb / s per channel and up to 6.4 Gb / s with four channels.

There are also two disadvantages, quite significant:

1. The paws are golden and become unusable if the memory card is pulled out and inserted into the slot more than 10 times (approximately).

2. Overpriced, but many find very good use of this memory and are willing to pay big money for them.

That, perhaps, is all, we figured out the timings, names and denominations, now I will tell you a little about various important little things.

You probably saw the By SPD option in the BIOS "e when setting the memory frequency, what does this mean? SPD - Serial Presence Detect, this is a microcircuit on the module, in which all the parameters for the operation of the module are wired, these are the "default values" so to speak. Now, due to the appearance of "noname" companies, they began to write the name of the manufacturer and the date into this chip.

Register memory

Registered Memory it is a memory with registers that serve as a buffer between the memory controller and the module chips. Registers reduce the load on the synchronization system and allow you to collect a very large amount of memory (16 or 24 gigabytes) without overloading the controller circuits.

But this scheme has a drawback - the registers introduce a delay of 1 clock cycle for each operation, which means that register memory is slower than usual, all other things being equal. That is - the overclocker is not interested (and it is very expensive).

Everyone is now shouting about Dual channel - what is it?

dual channel- dual channel, this allows you to access two modules at the same time. Dual channel is not a module type, but a function integrated into the motherboard. Can be used with two (preferably) identical modules. It turns on automatically when there are 2 modules.

Note: to activate this function, you need to install modules in slots of different colors.

Parity and ECC

Memory with Parity it is a parity-checked memory capable of detecting some types of errors.

Memory with ECC This is an error-correcting memory that allows you to find and also correct the error of one bit in a byte. Used mainly on servers.

Note: it is slower than usual, not suitable for people who love speed.

I hope that after reading the article you have dealt with the more popular "obscure concepts".

Any DIMM memory module has a small SPD (Serial Presence Detect) chip, in which the manufacturer records information about the operating frequencies and the corresponding delays of the memory chips necessary to ensure the normal operation of the module.

Information from the SPD is read by the BIOS during the self-test phase of the computer before the operating system is loaded and allows you to automatically optimize the memory access parameters.

AMD Radeon Software Adrenalin Edition Driver 19.9.2 Optional

The new AMD Radeon Software Adrenalin Edition 19.9.2 Optional driver improves performance in Borderlands 3 and adds support for Radeon Image Sharpening.

Cumulative windows update 10 1903 KB4515384 (added)

On September 10, 2019, Microsoft released a cumulative update for Windows 10 version 1903 - KB4515384 with a number of security improvements and a fix for a bug that broke Windows work Search and caused high CPU usage.

Driver Game Ready GeForce 436.30 WHQL

NVIDIA has released the Game Ready GeForce 436.30 WHQL driver package, which is designed for optimization in games: "Gears 5", "Borderlands 3" and "Call of Duty: Modern Warfare", "FIFA 20", "The Surge 2" and "Code Vein", fixes a number of bugs seen in previous releases, and expands the list of displays in the G-Sync Compatible category.

AMD Radeon Software Adrenalin 19.9.1 Edition Driver

First September issue graphics drivers AMD Radeon Software Adrenalin 19.9.1 Edition is optimized for Gears 5.

Questions

What memory limits are imposed by modern operating systems of the Windows family?

Obsolete, but still found in some places, operational Windows systems 9x/ME can only work with 512 MB of memory. And although large-volume configurations are quite possible for them, this causes much more problems than benefits. Modern 32-bit Windows versions 2000/2003/XP and Vista theoretically support up to 4 GB of memory, but no more than 2 GB is actually available for applications. With a few exceptions - OS entry level Windows XP Starter Edition and Windows Vista Starter can run with no more than 256 MB and 1 GB of memory, respectively. The maximum supported size of 64-bit Windows Vista varies by version and is:

  • Home Basic - 8 GB;
  • Home Premium - 16 GB;
  • Ultimate - Over 128 GB;
  • Business - More than 128 GB;
  • Enterprise - More than 128 GB.

What is DDR SDRAM?

DDR (Double Data Rate) memory provides data transfer over the memory-to-chipset bus twice per clock, on both edges of the clock signal. Thus, when the system bus and memory operate at the same clock frequency, the bandwidth of the memory bus is twice that of conventional SDRAM.

Two parameters are usually used in the designation of DDR memory modules: either the operating frequency (equal to twice the clock frequency) - for example, the clock frequency of the DR-400 memory is 200 MHz; or peak throughput (in Mb/s). The same DR-400 has a bandwidth of approximately 3200 Mb / s, so it can be referred to as PC3200. At present, DDR memory has lost its relevance and in new systems it has been almost completely superseded by the more modern DDR2. however, in order to keep afloat a large number of older computers that have DDR memory installed, it is still being released. The most common 184-pin DDR modules are PC3200 and, to a lesser extent, PC2700. DDR SDRAM may have Registered and ECC variants.

What is DDR2 memory?

DDR2 memory is the successor to DDR and is currently the dominant memory type for desktops, servers, and workstations. DDR2 is designed to operate at higher frequencies than DDR, is characterized by lower power consumption, as well as a set of new features (prefetch 4 bits per clock, built-in termination). In addition, unlike DDR chips, which were produced both in TSOP and FBGA packages, DDR2 chips are produced only in FBGA packages (which provides them with greater stability at high frequencies). DDR and DDR2 memory modules are not only electrically and mechanically compatible with each other: 240-pin brackets are used for DDR2, while 184-pin brackets are used for DDR. Today, the most common memory operating at a frequency of 333 MHz and 400 MHz, and referred to as DDR2-667 (PC2-5400/5300) and DDR2-800 (PC2-6400), respectively.

What is DDR3 memory?

Answer: The third generation DDR memory - DDR3 SDRAM should soon replace the current DDR2. The performance of the new memory has doubled compared to the previous one: now each read or write operation means access to eight groups of DDR3 DRAM data, which, in turn, using two different reference oscillators, are multiplexed over the I / O pins at a frequency of four times the clock frequency. Theoretically, effective DDR3 frequencies will be in the range of 800 MHz - 1600 MHz (at clock frequencies of 400 MHz - 800 MHz), thus, the marking of DDR3 depending on the speed will be: DDR3-800, DDR3-1066, DDR3-1333, DDR3-1600 . Among the main advantages of the new standard, first of all, it is worth noting significantly lower power consumption (supply voltage DDR3 - 1.5 V, DDR2 - 1.8 V, DDR - 2.5 V).

What is SLI-Ready Memory?

Answer: SLI-Ready-memory, otherwise - memory with EPP (Enhanced Performance Profiles - profiles to increase performance), created by the marketing departments of NVIDIA and Corsair. EPP profiles, in which, in addition to the standard memory timings, the value of the optimal supply voltage of the modules, as well as some Extra options, are written to the SPD chip of the module.

Thanks to EPP profiles, the complexity of self-optimization of the memory subsystem operation is reduced, although "additional" timings do not have a significant impact on system performance. So there is no significant gain from using SLI-Ready memory compared to conventional manually optimized memory.

What is ECC memory?

ECC (Error Correct Code - error detection and correction) is used to correct random memory errors caused by various external factors, and is an improved version of the "parity check" system. Physically, ECC is implemented as an additional 8-bit memory chip installed next to the main ones. Thus, ECC modules are 72-bit (as opposed to standard 64-bit modules). Some types of memory (Registered, Full Buffered) are available only in ECC version.

What is Registered Memory?

Registered (registered) memory modules are mainly used in servers that work with large amounts of RAM. All of them have ECC, i.e. are 72-bit and, in addition, contain additional register chips for partial (or full - such modules are called Full Buffered, or FB-DIMM) data buffering, thereby reducing the load on the memory controller. Buffered DIMMs are generally incompatible with non-buffered ones.

Is it possible to use Registered instead of regular memory and vice versa?

Despite the physical compatibility of the connectors, ordinary unbuffered memory and Registered memory are not compatible with each other and, accordingly, the use of Registered memory instead of ordinary memory and vice versa is impossible.

What is SPD?

Any DIMM memory module has a small SPD (Serial Presence Detect) chip, in which the manufacturer records information about the operating frequencies and the corresponding delays of the memory chips necessary to ensure the normal operation of the module. Information from the SPD is read by the BIOS during the self-test phase of the computer before the operating system is loaded and allows you to automatically optimize the memory access parameters.

Can memory modules of different frequency ratings work together?

There are no fundamental restrictions on the operation of memory modules of different frequency ratings. In this case (at auto tuning memory according to SPD data), the speed of the entire memory subsystem will be determined by the speed of the slowest module.

Yes, you can. The high standard clock frequency of the memory module does not affect its ability to work at lower clock frequencies, moreover, due to low timings, which are achievable at lower module operating frequencies, the memory latency decreases (sometimes significantly).

How many and what kind of memory modules should be installed in the system board in order for the memory to work in dual-channel mode?

In the general case, to organize memory operation in dual-channel mode, it is necessary to install an even number of memory modules (2 or 4), and in pairs the modules must be of the same size, and preferably (although not necessarily) from the same batch (or, at worst, the same manufacturer). In modern motherboards, the memory slots of different channels are marked with different colors.

The sequence of installing memory modules in them, as well as all the nuances of the operation of this board with various memory modules, are usually detailed in the manual for the motherboard.

Which manufacturers should pay attention to the memory in the first place?

There are several memory manufacturers worthy of a good reputation in our market. These will be, for example, OCZ, Kingston, Corsair, Patriot, Samsung, Transcend brand modules.

Of course, this list is far from complete, but when buying memory from these manufacturers, you can be sure of its quality with a high degree of probability.

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