Corsair Company is a constant participant of all test sessions devoted to overclocker’s memory on our site. And this is not surprising at all, actually, as the product range offered by this manufacturer is quite extensive not only from the feature prospective, but also from the price point. I have to say that Corsair offers the enthusiasts two kits with the memory capacity of 2GB and working frequency of 800MHz. They are TWIN2X2048-6400С3 and TWIN2X2048-6400С4. The former is a more expensive solution supporting 3-4-3-9 timings, while the latter one uses 4-4-4-12 timing settings. We got a more affordable solution for our today’s tests: the kit with less aggressive timings and broader availability in retail these days.
Corsair TWIN2X2048-6400С4 memory kit consists of two identical DIMMs, each 1GB big and each with its own part number – CM2X1024-6400C4. According to the manufacturer, these modules work at the nominal frequency of 800MHz, timings set at 4-4-4-12, 2T Command rate and 2.1V voltage.
I would like to point out right away that Corsair TWIN2X2048-6400С4 kit can be regarded as a close relative of the recently reviewed Corsair TWIN2X2048-8500С5 kit (for details see our article called Choosing the Right Memory for Core 2 Duo Platform - Part 2: DDR2-1000, DDR2-1067 SDRAM). And it is not only about the exterior design similarity. Of course, they look similar. Like many other Corsair overclocker’s kits, both sides of the TWIN2X2048-6400С4 DIMMs are covered with traditional black-anodized aluminum heat-spreaders. There are stickers with the manufacturer’s logo and product specifications on top of each heat-spreader. However, the major similarity between Corsair TWIN2X2048-6400С4 and the recently reviewed other Corsair solution is hidden right beneath these heat-spreaders: both these modules are built using the same Micron chips. And the difference between the Corsair TWIN2X2048-6400С4 and the faster modification is determined mostly by the voltage, which equals 2.1V in our case and 2.2V in case of memory modules designed to work at 1066MHz frequency.
The stickers on the heat-spreaders of the memory modules contain the information about the part number, memory capacity, nominal frequency and timings. I would like to draw your attention to the fact that we have memory modules of revision 1.2, which has also been indicated on the stickers. The distinguishing feature of this modification is that it has been certified to work in SLI systems, i.e. they support EPP (Enhanced Performance Profile) technology from Nvidia.
You can see all this in the modules’ SPD:
To ensure that these memory modules are compatible with different mainboards, there are two work modes listed in the standard PSD field: with 4-4-4-13 timings and 533MHz frequency and 5-5-5-18 timings and 800MHz frequency. However, these numbers do not actually reflect the real capabilities of the Corsair TWIN2X2048-6400С4 memory kit. The manufacturer suggests that you should check out the potential of this solution in the EPP section. This section serves to automatically set up the memory subsystem of platforms built around any Nvidia nForce 500 chipsets based mainboards. This is where we come across the DDR2-800 mode with 4-4-4-12 timing settings that should work at 2.0V Vdimm, according to EPP. Moreover, Corsair engineers have also declared in EPP for Corsair TWIN2X2048-6400С4 modules the 1066MHz frequency with 5-5-5-15 timings and 2.2V voltage. In other words, the PC2-6400 memory modules from Corsair we are reviewing today turned out similar to Corsair TWIN2X2048-8500С5 not only on the component level: even the manufacturer stresses that they are identical, as you can see clearly in the SPD/EPP of these modules.
Very intriguing situation. So far we have got a few very clear indications that Corsair TWIN2X2048-6400С4 and Corsair TWIN2X2048-8500С5 should be exactly the same. It is really interesting to see whether our practical testing will confirm this statement, especially since the today’s memory kit is more than $100 cheaper than the TWIN2X2048-8500С5. The graph below shows the maximum frequencies when the tested memory remained stable.
Although we are no kids anymore, Corsair once again makes us believe in wonders. Corsair TWIN2X2048-6400С4 really turned out very close in performance to the more expensive memory. Although it is running not completely neck and neck, the performance difference can be explained by lower nominal voltage of the PC2-6400 modules. In other words, Corsair TWIN2X2048-6400С4 is an excellent memory kit that can easily perform the role of PC2-8500 SDRAM. With the timings set to 5-5-5-15 it hits far beyond 1067MHz. As for the nominal latency settings, Corsair TWIN2X2048-6400С4 works stably and reliably at up to 950MHz frequencies.