Since ATI put quite a lot of emphasis on the overclocking abilities of its RD580 chipsets, we had to compare the latest Asus Crossfire Xpress 3200 motherboard, A8R32-MVP, with its nForce4 SLI X16 counterpart, the A8N32-SLI. Which would be the better overclocker?

In order to have some decent memory for this overclocking project, we selected OCZ's EL-DDR PC4800 Platinum Edition. These units are rated CL2.5-4-4-8 with 1T timings and up to 300 MHz, which corresponds to DDR600 speed. Memory voltage was set to 3.1 V.

We were able to reach a maximum of 390 MHz base clock speed with ATI's Crossfire Xpress 3200 chipset; 400 MHz would still allow us to boot Windows, but the system became unstable. The surprising thing was that the same clock speed could be reached with the nForce4 SLI X16 motherboard.

Another interesting topic is the HyperTransport link speed that a platform is capable of sustaining when running overclocked. ATI had high expectations here, but unfortunately for them, it is the nForce4 SLI X16 motherboard that reached as much as 1,600 MHz (320 MHz base clock x5). We were not able to get more than 1,350 MHz HyperTransport speed (270 MHz base clock x5) with the Crossfire Xpress 3200 motherboard by Asus, even though 1,500 MHz was achieved during ATI's RD580 product briefing two weeks ago.

HyperTransport Speeds

We could not exceed 1,350 MHz HyperTransport speed with the new Asus A8R32-MVP motherboard without creating an unstable system.

A 1,600 MHz HyperTransport speed was reliable with the Asus A8N32-SLI.