Now that we’ve got some general impressions about the TWIN2X2048-8888C4DF, it’s time to check this kit out in practice. The testbed was configured like follows:
- Intel Core 2 Extreme X6800 CPU (LGA775, 2.93GHz, 4MB L2)
- ASUS P5B Deluxe mainboard (LGA775, Intel P965 Express)
- PowerColor X1900 XTX 512MB graphics card (PCI Express x16)
- Maxtor MaXLine III 250GB HDD (Serial ATA-150)
- Microsoft Windows XP SP2 with DirectX 9.0c
We assembled the testbed around an Intel processor for today’s tests because such systems are the more likely environment for the rather expensive PC2-8888 modules to be used in. Although fast memory would produce a bigger effect in Socket AM2 systems (the speed of CPU-memory communication is limited by the bandwidth of the FSB bus on LGA775 platforms), it won’t be used there often. After the introduction of Core 2 Duo processors, AMD’s CPUs have been relegated to the position of products for inexpensive entry-level and mainstream computers. Installing expensive memory into an inexpensive computer system doesn’t make much sense. There will be exceptions, though. Corsair itself tests its Dominator series modules on an ASUS M2N32 Deluxe mainboard that supports AMD processors.
Let’s take one more look at the modules before installing them into the testbed. Each module has a sticker with a module part number (CM2X1024-8888C4D) which differs from the part number of the whole kit. Besides that, the sticker shows you the frequency, capacity and timings of the module. There’s no voltage info here.
The modules’ SPD contains the following data:
The SPD information contains DDR2-533 and DDR2-800 modes for better compatibility with mainboards. It means you have to configure this kit manually in the mainboard’s BIOS Setup on your computer. The EPP data (Enhanced Performance Profile) may be of some help, but only on mainboards that are based on Nvidia’s chipsets. The EPP contains information about the single overclocked mode covered in the specs: 1100MHz, 4-4-4-12 timings and 2T Command Rate.
Tested at 2.4V voltage and with the cooler installed, the Corsair TWIN2X2048-8888C4DF kit showed the following results (the graphs show the highest frequencies the system was stable at for every set of timings). The stability of the system was verified by running three utilities: Memtest86, S&M and Prime95.
The diagram shows that the Corsair TWIN2X2048-8888C4DF kit is a versatile product, just like the rest of memory modules based on Micron chips. It can be used at frequencies up to 600MHz with as aggressive timings as 3-2-2-8. With 3-3-3-10 timings this memory hits the 800MHz mark. At its default 4-4-4-12 timings, the kit is operable at frequencies up to an impressive 1150MHz, providing a kind of safety margin above its specified 1111MHz. Setting the timings even higher doesn’t affect the frequency potential of the modules much. But even despite this, the Corsair TWIN2X2048-8888C4DF kit is to be acknowledged as the fastest DDR2 SDRAM kit for today. No other memory has ever performed like that in our labs.
It should be noted that the memory cooler supplied with Corsair Dominator memory doesn’t have a big effect on the modules’ overclockability. The cooler just guarantees good thermal conditions. Particularly, when we used the memory in its default mode (1111MHz with 4-4-4-12 timings), it was about 50°C hot without the cooler (under full load, on an open testbed and at an ambient temperature of 22°C) and only 33°C with the cooler.
Yet another curious fact we discovered in this test is that the frequency potential of the reviewed memory is greatly reduced when its voltage is lowered to 2.2V, which is the unofficial standard for a majority of other overclocker-friendly memory kits. For example, the Dominator kit was stable only as DDR2-1085 with 4-4-4-12 timings at this voltage.