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Corsair DHX 8GB DDR2 tested

by on13 May 2008


Review: Noticeably faster than 2GB


Most of us will stick to DDR2 memory, and the most common reason for this is the price of DDR3 memory;  besides being expensive it requires a new motherboard. Other reasons would be a very small performance increase that this would result in. Still, more memory means better performance, and low DDR2 prices that we're seeing these days are a good opportunity to feed our rigs some extra juice.

A computer with 1 or 2GB of memory is the norm these days, but Vista users will require more. 4GB is advisable, but 2GB will usually be sufficient. Although 32-bit Vista can’t utilize 4GB of memory, you’re still set because the system will be able to access 3.5GB, which is 75% more than 2GB.

This will prove enough for most of us, but if you’re using a 64-bit OS, why not utilize its good sides and buy 8GB of memory that you can buy virtually anywhere and at a good price? We can’t promise that it’ll benefit you in each segment, but if you’re, for instance, trying to cram a huge video into the memory for editing – then this will be a godsend. Still, you’ll rarely need more than 4GB, even with the latest games on the market.

A nice thing about Vista is that it automatically adapts to the amount of memory that it has at its disposal; meaning that if you have 8GB, the system will take up about 1GB for use. Vista will run with 512MB too, but in that case it will slow down to a crawl because it’ll access the data stored on the disk more often.

We decided to see how 8GB of memory runs in Vista 64bit SP1 OS. We used Corsair memory CM2X 2048 6400 C4 DHX with 4-4-4-12 latencies.


Low latencies at 800MHz are possible, even when using 8GB of memory. It took us four CM2X 2048 6400 C4 DHX memory modules, each packing 2GB, and they’re sold in sets of 4GB. It’s a nice feeling seeing them in your rig, but it’s even better knowing that it’s 8GB strong.



CM2X2048-6400C4DHX memory runs at 4-4-4-12 latencies. These modules are Corsair’s mainstream memory, but you can consider them performance memory. Just like performance Dominator series, our testing rig was in a mood for overclocking and we had no trouble hitting 1066MHz. We decided on 1066MHz just to see whether it will on Dominator’s speeds, also offered as 8GB kits.


We've known Corsair’s memory modules with Dual-Path Heat Xchange (DHX) technology for a while now. It’s a special module design with “thermal pad,” a copper layer extension of PCB module connected to two heatsinks, whereas another two lean on the memory. DHX Corsair modules pack four heatsinks, and the picture below shows it more clearly.


DHX technology enables better airflow among the heatsinks, thus improving the cooling and the memory frequencies as well. Together with the heatsink, memory is 5cm tall, so you should consider the width and height of your CPU cooler before you decide on this.




Vista reported 8GB of memory and we went on with our testing. We first installed Vista 64 OS and two games – Company of Heroes and Crysis. However, in order to prove that there’s an actual difference between 2 and 8GB we had to install a couple of programs. We opened up a couple of Word documents, Web browser windows, 3DStudio Max, Visual Studio 2008 and Photoshop. We used EVGA 780i motherboard with XFX’s 9800 GTX graphics card packing 512MB of memory.

The problem we encountered is that most apps we’re currently using are not native 64-bit, but rather 32-bit versions. Although some apps are memory-hungry, they’re still 32-bit and their limitation is the ability to address a maximum of 4GB. After that, they start writing to hard disk, but more apps running simultaneously will benefit from 8GB.

We played the games with 2GB of memory, and then we put in 8GB and did it all over again. We didn’t get an awesome performance increase, but with some 10 additional “memory-hungry” apps opened, the tables turned. 2GB of memory resulted in slow window opening and window switching. We tried to use ALT-TAB to minimize the game and check our mail and some sites, but that didn’t go well. The next picture clearly shows that we reached the limit.


8GB was a different story altogether, but we noticed that 2.4GB is enough for the system to run nicely.


One of the things where this much memory benefited was game loading time. In Company of Heroes with 2GB of memory, it took us a full minute to start the game, whereas 8GB resulted in only 32 seconds loading time. Unfortunately, the difference in loading time is visible only when there are other apps running in the background. In the case where the only thing running is your game, 2 and 8GB loading time is almost identical.



2GB of memory resulted in over 40 frames, but we had some glitches and stutters on certain levels. That was mostly because of minimal number of frames – 2.9 fps. We had no glitches with 8GB of memory, but the results were such that 8GB of memory didn’t quite impose itself as necessary. Performance-wise, 4GB was almost identical to 8GB.

It was tough getting an average framerate with all the apps opened in the background, but we took the average from a couple of runs. We mentioned that all we initially had were only two games and the OS, and the performance with 2GB and 8GB was more or less identical. With no apps running in the background, our OS and the game managed to fit in 2GB of memory.


Corsair memory, as many times before this, did its job nicely. With Dual-path Heat Xchange (DHX) technology on CM2X2048-6400C4DHX modules and low 4-4-4-12 latencies, we had a total of 8GB of fast CL4 memory. Basically, we tested 4 memory modules, each packing 2GB of DDR2 memory. The mere feeling that we have 8GB of memory at our disposal wasn’t enough, so we had to test it and see whether we actually need it.

4GB of CM2X2048-6400C4DHX memory, coming in two modules, costs €80, whereas 8GB or 4x2GB in two kits will set you back around €160. Low DDR2 prices make a jump to 8GB really tempting. Memory is one of the most important components of your computer, and since it directly affects performance your system will have breathing room and response times will decrease.

Response times were measured using ALT-TAB to exit the game and trying to continue the work we started before gaming. If you have Vista, 2GB will impose certain limits; available memory is simply gone after we ran a couple of demanding apps, and the system had to access the hard disk, that’s much slower. With 4GB, not to mention 8GB, we had no problems and everything we tried went without problems.

Gaming performance will greatly depend on how many apps are running in the background, so if you’re a fan of multi-tasking you might want to consider buying 8GB.

However, if your usual routine is booting your system up, starting a game, and then moving on to different apps, the only difference you’ll encounter is game loading time, that’s almost two times faster with 8GB.

Multi-tasking in Vista will definitely require more than 2GB of memory. One of the options that 8GB users will be able to do is turn off swapping files in virtual memory on their hard disks, but we don’t recommend this. Don’t even think about this if you have just 2GB of memory, because your system will need more soon enough, and it won’t have virtual memory.

At the end of the day we were quite pleased, because 8GB just might prove to be useful, especially if memory-hungry apps are your trade. When it comes to gaming, 8GB isn’t overly useful, because 4GB will prove to be more than enough. Priced at €80, 4GB seems like a good investment, and those who want more will have to splash out around €160.

Last modified on 13 May 2008
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