Corsair Dominator CM2X1024-10000C5D

Corsair's latest goodies: PC6400, PC8888 and PC10000 DIMMs. Corsair says that all Dominator DIMMs are hand-tested individually.

If you're familiar with Corsair's product nomenclature then you can decipher the product name CM2X1024-10000C5D:

• CM2X represents current 240-pin DDR2-SDRAM memory products (TWIN2X would be a matched memory pair)
• 1024 stands for the memory capacity of a single DIMM (1,024 MB or 1 GB)
• 10000 characterizes the equivalent JEDEC speed rating, which is based on the theoretical maximum throughput (1,250 MHz x 64 bit / 8 bits = 10,000 MB/s)
• 'C5' represents the CAS Latency (5 clock cycles)
• 'D' stands for Dominator
• An 'F' (if applicable) represents Corsair's proprietary memory fan solution

In contrast to the PC8888 part, the new PC10000 top model runs at a 12.5% faster clock speed, but the 4-4-4-12 (2T) timings had to be relaxed to 5-5-5-18 2T (CAS latency, tRCD, tRP, tRAS, command rate) which was necessary to ensure reliable operation at the high base clock speed of 625 MHz (1,250 MHz in DDR mode). The timing modification may sound like a step back (and from a performance standpoint it certainly is), but let's not forget that the official JEDEC DDR2 specification does not require anything faster than CL5-5-5-18 (2T) at DDR2-800 speed. No wonder that the memory's SPD has also been programmed for this speed, which should allow you to immediately operate this product in any AMD or Intel system that detects the memory parameters automatically.

While the default voltage for DDR2 memory at default timings is 1.8V, the Dominator CM2X1024-10000C5D requires as much as 2.4 V to run at its maximum speed. While we typically recommend paying close attention to motherboard selection, the selection is actually a bit limited at this point. Corsair asked us to use EVGA's nForce 680i SLI motherboard for testing, as many other motherboards aren't capable of supporting the new high-speed DIMMs (yet).

You might have already guessed it: 1,250 MHz is not the maximum clock speed, but it's the speed the new Dominator DIMMs are rated for. We were able to operate the memory at slightly above 1,300 MHz, but we did not try to go any further, as this would probably only work reliably with further voltage increase. At this point, after having seen the benchmark results, we don't see a lot of sense going this risky path and jeopardize the precious memory for marginal performance gains. At 2.4 V and full speed, the PC10000 DIMMs get warm, which is the reason why Corsair bundles the Dominator Airflow cooling system. The airflow is a clip-on frame, holding three 40 mm fans. It certainly does it job well, but our testing proved that it is not really necessary: We ran all our benchmarks without active cooling and we didn't run into any trouble.