The difference between ddr2 and ddr3 for a computer. How to distinguish ddr2 from ddr3 memory
To answer this question, it is worth familiarizing yourself with the specific characteristics of each model. This will help you find out how significant the difference is between DDR2 and DDR3 and is it worth changing the memory installed in your PC to a newer one?
DDR2 Specifications
1. Memory capacity: up to 16-32 GB.
2. Maximum frequency: 800 MHz.
3. Power consumption: 1.8 V.
4. Bandwidth: up to 2 Gb/s.
5. Volume of a single stick: up to 8 GB.
DDR3 Specifications
1. Memory capacity: up to 64 GB and above.
2. Maximum frequency: 1600 MHz.
3. Power consumption: 1.2-1.5 V.
4. Bandwidth: up to 3 Gb/s.
5. Volume of a single stick: up to 32 GB.
System upgrade
If you are thinking about upgrading your computer, then pay attention to the following points:
1. These two types of memory are not compatible;
2. On motherboards with slots for both types of memory, you cannot use DDR2 and DDR3 at the same time - you must select one type;
3. Newer motherboards may only contain DDR3 connectors.
Will the difference between DDR2 and DDR3 affect system performance? If the rest of the hardware remains the same, then the limitations of its maximum characteristics will not allow you to fully experience the increase in performance of the new type of memory. If you are ready to switch to a new platform, upgrade your motherboard and processor, then the issue of choosing a memory type is decided in favor of DDR3.
You can order a computer with the required configuration in the MOYO online store. Here you can buy modern computer equipment, peripherals and accessories at the most affordable prices.
If you periodically have to pick at hardware, and even old hardware, the problem is also relevant for you. This note describes how to determine the type of RAM by appearance and size.
“Personal computers” evolved quickly and they consistently used several different and incompatible types of RAM. Naturally, you can only put into your computer the type of RAM for which there is a suitable slot on the motherboard.
Historically, the first memory was SIMM with 30 contacts; it was installed on computers with processors from 286 to 486; now such memory is hardly used anywhere. The linear size of the memory module is 89.03 mm, and it looked like this:
IBM-compatible computers also used a 72-pin SIMM with a linear module size of 108.2 mm. There were 2 types of such modules - FPM (Fast Page Mode) and EDO (Extended Data Out).
FPM memory was installed on computer motherboards with a 486 processor and on the first Pentiums (until about 1995). After that, they switched to EDO. Unlike FPM, EDO begins fetching the next memory block at the same time it sends the previous block central processor.
Structurally, the modules are identical; they can be distinguished from each other only by markings. PCs that supported EDO could usually work with FPM, but there was no backward compatibility.
Since about 1996, most manufacturers began to support a type of SDRAM memory called DIMM (Dual In-line Memory Module). The main difference between DIMMs is that the contacts located on different sides of the module are independent, but on SIMM they were closed to each other and transmitted the same signals. The first DIMMs had 72 pins, and modern DDR4 modules, which formally belong to the same type, have as many as 288 pins.
The linear dimension of the DIMM is 133.8 mm. A standard 5.25-inch DIMM memory slot, by the way, has a size of 133.35 mm.
DIMM memory was very common until about 2001, being used by most Pentium and Celeron computers. After this, the time came for DDR and memory practically stopped being called “sim” or “dim”.
RIMM is a separate RAM standard that appeared in 1999. The architecture of RIMM memory differs significantly from DIMM/DDR; RIMM memory was practically not used in personal computers, but in game consoles Sony Playstation 2 and Nintendo 64 - yes. There are 184-, 168-, and 242-pin RIMMs.
DDR (Double Data Rate) became the next generation of SDRAM; such modules first appeared on the market in 2001. The main difference between DDR and classic SDRAM is that to speed up operation, instead of doubling the clock frequency, DDR modules transmit data twice per clock cycle.
DDR2 is a newer variant of DDR, theoretically 2 times faster. Such memory appeared in 2003, and in 2004 it became quite common. The main difference between DDR2 and DDR is the ability to operate at higher clock speeds, thanks to improvements in design. In appearance, DDR2 differs from DDR in the number of contacts, 240 versus 184 for the first DDR. The linear size of the module has not changed.
Hello, friends! In this article, we tried to answer many of your questions regarding RAM. ? How can I find out what RAM I have installed and how much? How to choose the right RAM for your computer. How do you know if your RAM is running in dual channel mode or not? What is better to buy, one 8GB DDR3 memory stick or two 4GB sticks each? And finally.
- If you are interested, or, also read our articles.
- Hello admin, one of my friends asks me to install more RAM. The computer properties show a capacity of 2 GB. We turned off the computer, opened the system unit, there was one stick of RAM, took it out, and there were no marks on it. Interestingly, it was not possible to determine the model of the motherboard. The computer was purchased a long time ago, so the question arose - how to find out the type of RAM it needs? After all, RAM differs in type, frequency and timing.
- Hi all! I wanted to buy additional RAM, I removed the cover of the system unit, took out the RAM stick and I can’t decipher the information written on it, the serial number is simply written there and that’s it. It is completely unclear at what frequency it operates and what type it is, DDR3 or DDR2. How to distinguish DDR3 from DDR2 memory, how do they differ in appearance?
- I have one stick of 4 GB DDR3-1600 RAM in the system unit, I want to install another stick, also 4 GB, but running at a higher frequency DDR3-1866. Will my computer work normally, and most importantly, in dual-channel mode?
My friend installed three RAM sticks of different sizes and frequencies into the system unit. Is this allowed? But what’s strange is that his computer works fine! - Tell me, how can I check whether my RAM works in dual-channel mode or not? And what conditions are needed for my memory to work in dual-channel mode. Same volume? Same frequency or same timings? How much faster does a computer run in dual-channel mode than in single-channel mode? They say that there is also a three-channel mode.
- What will work better, two sticks of 4 GB of RAM in dual-channel mode or one stick, but with a capacity of 8 GB, respectively, the memory mode will be single-channel?
To find out all the information about a RAM module, you need to carefully examine it; usually the manufacturer labels the RAM with the proper information about the frequency, volume and type of RAM. If there is no such information on the module, then you need to find out everything about the motherboard and the installed processor; sometimes this action turns into a whole investigation.
- Important Notes: Friends, do not forget that all new processors Intel Core i3, Intel Core i5, Intel Core i7 The RAM controller is located in the processor itself (previously it was controlled by the north bridge of the motherboard) and the memory modules are now directly controlled by the processor itself, the same applies to the latest AMD processors.
- This means that it doesn't matter what RAM frequency your motherboard supports. It is important what RAM frequency your processor supports. If your computer has a processorIntel Core i3, Intel Core i5, Intel Core i7, then the officially supported memory standards of these processors: PC3-8500 (DDR3-1066 MHz), PC3-10600 (DDR3-1333 MHz), PC3-12800 (DDR3-1600 MHz), it is at these frequencies that your RAM will operate, even if the motherboard's passport indicates that the motherboard can work with PC3-19200 high-frequency RAM memory sticks (DDR3-2400 MHz).
- It's another matter if your processor has unlocked multiplier, that is, with the letter “K” at the end, for example CPU Intel Core i7-4770 K, 3.5 GHz. An unlocked multiplier means that in a computer with such a processor you can install memory sticks of the highest frequency, for example DDR3-1866 MHz or DDR3-2400 MHz, such a processor can be overclocked and during overclocking the RAM will operate at its frequency of 2400 MHz . If you install the RAM stick DDR3-1866 MHz or DDR3-2400 MHz into a computer with a conventional processor, that is, with locked multiplier without letter" K” at the end, for exampleIntel Core i7-3770, 3.9 GHz then such a bar will work at best at a frequency DDR3-1600 MHz, and in the worst case, the computer will not boot. Therefore, buy RAM that is suitable for your processor.
- Concerning processorsAMD recent years, then they work with memoryPC3-10600 (DDR3-1333 MHz).
Firstly, the RAM stick itself should contain all the information you are interested in, you just need to read it correctly. I don’t argue, there are memory strips that have practically nothing on them, but we can handle them too.
For example, let’s take a Hynix RAM stick, it has the following information: 4 GB PC3 – 12800.
What does the following mean:
firstly, the volume is 4 GB,
secondly, 1Rx8 - Rank - a memory area created by several or all chips of a memory module, 1Rx8 are single-sided memory ranks, and 2Rx8 are double-sided memory ranks.
As you can see, this bar does not say that it is DDR2 or DDR3, but the throughput of PC3-12800 is indicated. PC3 is a designation for peak bandwidth belonging only to the DDR3 type (for DDR2 RAM the designation will be PC2, for example PC2-6400).
This means that our Hynix RAM stick is DDR3 and has PC3-12800 bandwidth. If the bandwidth of 12800 is divided by eight and you get 1600. That is, this DDR3 memory stick operates at a frequency of 1600 MHz.
Read everything about DDR2 and DDR3 RAM on the website
http://ru.wikipedia.org/wiki/DDR3 and everything will become clear to you.
Let's take another RAM module - Crucial 4GB DDR3 1333 (PC3 - 10600). This means the following: volume 4 GB, memory type DDR3, frequency 1333 MHz, PC3-10600 bandwidth is also indicated.
Manufacturer Patriot, capacity 1 GB, PC2 bandwidth – 6400. PC2 is a designation for peak bandwidth belonging only to the DDR2 type (for DDR3 RAM the designation will be PC3, for example PC3-12800). We divide the bandwidth of 6400 by eight and get 800. That is, this DDR2 memory stick operates at a frequency of 800 MHz.
One more plank- Kingston KHX6400D2 LL/1G
Manufacturer Kingston, bandwidth 6400, type DDR2, capacity 1 GB. We divide the bandwidth by 8, we get a frequency of 800 MHz.
But this stick of RAM has more important information, it has a non-standard microcircuit supply voltage: 2.0 V - set manually in the BIOS.
RAM modules differ in the size of the contact pads and the location of the cutouts. Using a cutout, you will not be able to install a RAM module in a slot not intended for it. For example, you cannot install a DDR3 memory stick in a DDR2 slot.
Everything is clearly visible in this diagram.
Sometimes there will be no clear information on the RAM module other than the name of the module itself. But the module cannot be removed, since it is under warranty. But by the name you can understand what kind of memory it is. For example
Kingston KHX1600 C9D3 X2K2/8G X, all this means:
KHX 1600 -> RAM operates at 1600 MHz
C9 -> Timings (Delays) 9-9-9
D3 -> RAM type DDR3
8G X -> Volume 4 GB.
You can simply type the name of the module in search engines and you will find out all the information about it.
For example, information from the AIDA64 program about my RAM. Kingston HyperX RAM modules are installed in RAM slots 2 and 4, memory type DDR3, frequency 1600 MHz
DIMM2: Kingston HyperX KHX1600C9D3/4GX DDR3-1600 DDR3 SDRAM
DIMM4: Kingston HyperX KHX1600C9D3/4GX DDR3-1600 DDR3 SDRAM
Is it possible to install RAM sticks with different frequencies into a computer?
The RAM frequency does not have to be the same. The motherboard will set the frequency for all installed RAM sticks according to the slowest module. But I want to say that often a computer with brackets of different frequencies is unstable.
Let's do a simple experiment. For example, let's take my computer, it has two identical Kingston HyperX RAM modules, memory type DDR3, frequency 1600 MHz.
If I run the AIDA64 program on my Windows 8, it will show the following information (see the following screenshot). That is, the program AIDA64 shows simple technical characteristics of each RAM stick; in our case, both sticks have a frequency1600 MHz. But the programAIDA64 does not show at what frequency the RAM modules are currently operating; this needs to be looked at in another program called CPU-Z.
If you run the free CPU-Z program and go to the Memory tab, it will show you exactly what frequency your RAM sticks are running at. My memory operates in dual-channel Dual mode, frequency 800 MHz, since the memory is DDR3, its effective (double) speed is 1600 MHz. This means that my RAM sticks operate exactly at the frequency for which they are designed: 1600 MHz. But what will happen if next to your RAM strips operating at a frequency 1600 MHz I will set another bar with frequency 1333 MHz!?
Let's install an additional DDR3 memory stick in my system unit, operating at a lower frequency of 1333 MHz.
Let's look at what AIDA64 shows, the program shows that an additional 4 GB stick is installed, with a frequency of 1333 MHz.
Now let’s run the CPU-Z program and see at what frequency all three sticks operate. As we can see, the frequency is 668.7 MHz, since the memory is DDR3, its effective (double) speed is 1333 MHz.
That is, the motherboard automatically set the operating frequency of all RAM sticks to the slowest module at 1333 MHz.
It is not advisable to install RAM sticks in your computer with a frequency higher than what the motherboard supports. For example, if your motherboard supports a maximum RAM frequency of 1600 MHz, and you installed a RAM module operating at a frequency of 1866 on your computer, then in the best case, this module will operate at a lower frequency of 1600 MHz, and in the worst case, the module will operate at its frequency 1866 MHz, but the computer will periodically reboot itself or you will get a blue screen when you boot the computer, in this case you will have to enter the BIOS and manually set the RAM frequency to 1600 MHz.
Timings(signal delay) determine how often the processor can access RAM. If you have a quad-core processor and it has a large second-level cache, then too long timings are not a problem, since the processor accesses RAM less often. Is it possible to install RAM sticks with different timings in a computer? The timings also do not have to match. The motherboard will automatically set timings for all modules according to the slowest module.
What conditions are needed for my memory to work in dual-channel mode? Before buying RAM, you need to study as much information as possible about the motherboard. All information about your motherboard can be found in the manual that came with it upon purchase. If the manual is lost, you need to go to the official website of your motherboard. You will also find the article “How to find out the model and all information about your motherboard” useful.Most often these days there are motherboards that support the RAM operating modes described below. Dual Mode (two-channel mode, most common)– if you look closely at the motherboard, you can see that the RAM slots are painted in different colors. This was done on purpose and means that the motherboard supports dual-channel RAM operation. That is, two RAM modules with the same characteristics (frequency, timings) and the same volume are specially selected and installed in RAM slots of the same color.
If your computer has one stick of RAM installed, but the motherboard supports dual-channel mode, you can buy an additional stick of RAM of exactly the same frequency and capacity and install both sticks in DIMM slots of the same color.
Is there an advantage to dual channel mode over single channel mode?
During normal work on a computer, you will not notice the difference, but when working in applications that actively use RAM, such as Adobe Premiere Pro (video editing), (Canopus) ProCoder (video encoding), Photoshop (working with images), games, the difference can be feel.
Note: Some motherboards will operate in dual-channel mode even if you install RAM modules of different sizes in the same color DIMM slots. For example, you will install a 512MB module in the first DIMM slot, and a 1GB stick in the third slot. The motherboard activates dual-channel mode for the entire volume of the first 512MB stick, and for the second stick (interestingly) also 512MB, and the remaining 512MB of the second stick will work in single-channel mode.
How do I know if my RAM is working in dual channel mode or not? Download the free CPU-Z program and go to the Memory tab, look at the Channel parameter in our case - Dual, which means the RAM operates in dual-channel mode. If the Channels parameter is Single, then the RAM operates in single-channel mode.
My opinion is that during normal work on a computer they will work the same, I personally didn’t notice much of a difference. I worked for a long time on a computer with one large stick of RAM and the performance was the same as on exactly the same computer with two sticks of RAM running in dual-channel mode. A survey of friends and acquaintances of system administrators confirmed me in this opinion. But when working with programs that actively use RAM, for example Adobe Premiere Pro, Canopus ProCoder, Photoshop, games, a computer with two sticks of RAM will work faster.
Of course it is possible, but not advisable. The computer will work more stable if it implements the RAM operating mode recommended in the motherboard data sheet. For example, two-channel mode.
Memory manufacturers have done well to promote their latest high-end products: DDR3-2000 speeds are currently considered cutting-edge for Intel platforms based on Intel P35, X38, X48 chipsets for enthusiasts or the new nVidia 7 line. But does it make sense to buy such memory? While mainstream DDR2 memory has reached ridiculously low price levels (you can buy two 2GB DDR2-800 memory modules for $90-$100), DDR3 memory at 1600 speeds and above costs five times more, and the performance gains are negligible. In essence, for the vast majority of users, the difference between mainstream and high-end memory is very small.
The meaning of Random Access Memory (RAM) has changed greatly over time. At the beginning of the millennium, there was a significant difference in performance between CL2 and CL3 latencies, when the first generation SDRAM memory type with PC100 and PC133 speeds was popular. But now, when using high-speed DDR2 or DDR3 SDRAM memory modules, the difference in performance between low and high timings is almost negligible. Although memory latencies increase from generation to generation (CL2/3 with DDR1, CL3-5 with DDR2, CL5 and higher with DDR3), they have not changed much since clock speeds double with each generation, potentially negating the increase in latencies. Thus, effective delays remain virtually unchanged, but throughput has increased significantly.
Another issue with memory for enthusiasts that is only indirectly related to performance is that overclockers expect extreme flexibility from components when they want to squeeze the maximum performance out of their systems. Increasing the system bus clock speed is often the only way to increase the CPU clock speed, which automatically overclocks the memory, since the memory bus frequency directly depends on the FSB frequency. Since you don't want to lose performance due to limited memory speed, you may need high-speed memory to achieve maximum system performance. However, this scenario is only valid for hardcore overclockers, since the advantage of high-speed memory over slow memory is very insignificant if other components and parameters remain the same.
We want to find out how important memory speed and latency really are. For testing, we assembled a system based on Socket 775, which we ran with two different processors: a new 3.16-GHz Core 2 Duo E8500 processor on a 45-nm Core 2 Duo Wolfdale core with 6 MB of L2 cache, and a single-core 3.73- GHz Pentium 4 Extreme Edition processor. We decided to go with the old Netburst P4 single-core P4 processor because it has a smaller and less efficient cache than the Core 2 Duo. Both processors were tested at speeds of DDR2-667, DDR2-800 and DDR2-1066, as well as DDR3-1066 and DDR3-1333, using low and high latencies each time. However, P4 could not be tested on DDR3-1333, since this would require the FSB1333 bus.
Memory selection
The memory market is in the process of transitioning from DDR2 to the more power efficient and higher density DDR3 memory; this process will continue until the end of 2008. DDR2 is available at speeds of 800 and 1066, while DDR3 has so far increased the speed from 800 to 1333 MHz (effective frequency indicated). Faster products are still aimed at enthusiasts, as the platforms do not yet officially support speeds of 1600+.
Both DDR2 and DDR3 are based on the principle of twice the data transfer per clock cycle, i.e. Data is transmitted on the rise and fall of the clock pulse. Each new generation of DDR features smaller transistors, lower voltage, and higher memory density. While the internal clock speeds did not change, the interface (I/O buffer) clock speed increased due to the increase in prefetch size. DDR3-1600 memory runs at a physical clock speed of 200 MHz, but with a prefetch size of 8 bits. The interface clock frequency is 800 MHz, but thanks to the double data transfer technology, this is equivalent to a frequency of 1,600 MHz. The base clock speed of DDR2-800 memory is also 200 MHz, but the prefetch size is 4 bits.
As mentioned earlier, performance is not a sufficient reason to switch from one generation of memory to another. Of greater interest is memory density. For now, 1-GB memory modules (1-Gbit chips) can be considered mainstream in the DDR2 memory market, but DDR3 memory will soon begin to dominate when 2-GB DDR3 modules become affordable, and AMD will also switch to this memory (closer to the end of the year ).
Which memory is better to buy?
Be that as it may, the most advantageous offer can be found on the market for mass-produced DDR2 modules. If it all comes down to money, then you should pay attention to any set of 2x 1 GB DDR2 with DDR2-800 speeds. As the test results will show, only memory with significantly higher speeds (and at a significantly higher price) can provide small performance gains. We don't even recommend going after DDR3 motherboards unless you're buying a high-end product. When you buy a motherboard for several hundred dollars and a Core 2 Quad processor in the same price range, plus other decent system components, it is quite acceptable to spend more on memory. But for users on a limited budget this is not acceptable.
Two-gigabyte memory kits with two DDR2-800 modules start at about $40. This can be considered a good buy, considering that 2 GB of main memory is enough to run all major applications and games. Larger memory capacity, i.e. 4 GB requires a 64-bit operating system because 32-bit versions of Windows XP and Windows Vista will only be able to use 3 GB of RAM. While 64-bit versions are also available, work almost as fast, and driver support has improved significantly, we strongly recommend that you ensure that your devices and applications will run in a 64-bit environment.
| DDR2 specification | ||||||
| Standard title | Memory frequency | Takt time | Bus frequency | Module name | ||
| DDR2-400 | 100 MHz | 10 ns | 200 MHz | 400 million | PC2-3200 | 3,200 MB/s |
| DDR2-533 | 133 MHz | 7.5 ns | 266 MHz | 533 million | PC2-4200 | 4,266 MB/s |
| DDR2-667 | 166 MHz | 6 ns | 333 MHz | 667 million | PC2-5300 | 5,333 MB/s |
| DDR2-800 | 200 MHz | 5 ns | 400 MHz | 800 million | PC2-6400 | 6,400 MB/s |
| DDR2-1066 | 266 MHz | 3.75 ns | 533 MHz | 1,066 million | PC2-8500 | 8,533 MB/s |
At the moment, we recommend that ordinary users pay attention to DDR2-800 memory. Fast timings (low CL latencies) are preferable, but don't shell out much more money for them as the difference is small. DDR2-1066 memory is important for AMD Phenom processor systems so that their memory controllers can handle faster memory.
| DDR3 specification | ||||||
| Standard title | Memory frequency | Takt time | Bus frequency | Number of data transfers per second | Module name | Peak Data Rate |
| DDR3-800 | 100 MHz | 10 ns | 400 MHz | 800 million | PC3-6400 | 6,400 MB/s |
| DDR3-1066 | 133 MHz | 7.5 ns | 533 MHz | 1,066 million | PC3-8500 | 8,533 MB/s |
| DDR3-1333 | 166 MHz | 6 ns | 667 MHz | 1,333 million | PC3-10600 | 10,667 MB/s |
| DDR3-1600 | 200 MHz | 5 ns | 800 MHz | 1,600 million | PC3-12800 | 12,800 MB/s |
As for DDR3 memory, we recommend holding off on purchasing it, since high-speed models are still much more expensive than DDR2 memory and do not provide better performance. Even for high-capacity memory kits, the following can be said: kits of four 2GB DDR2 modules cost much less than the same DDR3 memory.
Here, once again, I was asked how one can determine the type of RAM by its appearance. Because This question comes up periodically, I decided that it was better to show it once than to explain it a hundred times, and write an illustrated mini-review of types of RAM for PCs.
Not everyone is interested in this, that’s why I’m hiding it under the cat. Read
The most common types of RAM that have been and are used in personal computers are commonly called SIMM, DIMM, DDR, DDR2, DDR3. You are unlikely to see SIMMs and DIMMs anymore, but DDR, DDR2 or DDR3 are now installed in most personal computers. So, in order
SIMM
SIMM for 30 contacts. Used in personal computers with processors from 286 to 486. Now it is already a rarity. 
SIMM for 72 contacts. This type of memory was of two types: FPM (Fast Page Mode) and EDO (Extended Data Out).
The FPM type was used on computers with 486 processors and the first Pentiums until 1995. Then EDO appeared. Unlike its predecessors, EDO begins fetching the next block of memory at the same time it sends the previous block to the CPU.
Structurally they are identical, they can only be distinguished by markings. Personal computers that supported EDO could also work with FPM, but the opposite was not always the case.
DIMM
This is the name given to the memory type SDRAM (Synchronous DRAM). Starting in 1996, most Intel chipsets began to support this type of memory module, making it very popular until 2001. Most computers with Pentium and Celeron processors used this type of memory.
DDR
DDR (Double Data Rate) was a development of SDRAM. This type of memory module 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 per clock cycle.
DDR2
DDR2 (Double Data Rate 2) is a newer variant of DDR that should theoretically be twice as fast. DDR2 memory first appeared in 2003, and chipsets supporting it appeared in mid-2004. The main difference between DDR2 and DDR is the ability to operate at a significantly higher clock frequency, thanks to improvements in design. In appearance it differs from DDR in the number of contacts: it has increased from 184 (for DDR) to 240 (for DDR2).
DDR3
Like DDR2 memory modules, they are produced in the form of a 240-pin printed circuit board (120 pins on each side of the module), but are not electrically compatible with the latter, and for this reason have a different “key” location. 
And finally, there is another type of RAM - RIMM (Rambus). Appeared on the market in 1999. It is based on traditional DRAM, but with a radically changed architecture. This type of RAM did not take root in personal computers and was used very rarely. Such modules were also used in the Sony Playstation 2 and Nintendo 64 game consoles.
SIMM for 30 contacts.