We do Crossfire—SLI tests

We got a new Asus A8R32 MVP Deluxe socket 939 motherboard with the new ATI Crossfire chipset (that we're not permitted to talk about now, but will do so in the next issue) and built up a new computer. AMD sent us a new dual-core 2.604-GHz 64 FX-60 processor and we beefed up the system with a 550W power supply and 1 GByte of 400-MHz DDR; we were ready to rock and roll.

Sitting next to the CF-based system was an SLI-based system, also with a killer AMD 64 FX-60 dual-core processor. This one was running at 2.614 GHz, a tad faster but less than a half percent.

We plugged in two Radeon X1900XTX AIBs, each with 512 MBytes, and in the SLI system we had two GeForce 7800GTX with 512 MBytes, so it was pretty much an apples-to-apples comparison.

And then we ran 3Dmark06. The results are shown in the chart above.

We were quite frankly surprised at the CF/X1900 performance. The ATI Catalyst driver package comes with a little over-clocking applet that lets you (at your own risk) crank up the GPU clock and, independently, the memory clock. We didn't do that for the tests, although we did do it for experimental purposes and found that it didn't really contribute that much, and at 1600 x 1200 with 4xAA, the system became very unstable, so there doesn't seem to be any good reason for turning up the clocks.

So this week, and probably for a few more weeks till the Nvidia 7900 shows up, ATI's Crossfire is king of the hill, right out of the box with no tweaks or supercharging.