We started by running an Asus Blitz Formula P35 board with OCZ PC2-9200 Reaper memory to get some baseline figures and rapidly reached a handful of conclusions. The first is that PCMark05 reports lower graphics performance when you use a pair of HD 2900 XT graphics cards in CrossFire while the 3DMark06 figures head off to the stratosphere. 3DMark06 is correct in this instance and PCMark05 is wrong but more annoyingly than that we also carried out some runs with Bapco's SYSmark 2007 benchmark and found that it doesn't think much of CrossFire or overclocking.
The Blitz Formula performed very nicely and we were able to raise the FSB from 1,333MHz to 1,600MHz to give a clock speed of 3.51GHZ, although this meant we had to play with the memory divider and drop the memory speed from 1,067MHz to 975MHz. This raised system performance by eight per cent.
Then we ran the Gigabyte X38T with the OCZ memory and found, unsurprisingly, that performance is identical to the Blitz at standard speeds. Raising the FSB to 1,600MHz made the system unstable so we ended up at a figure of 1,520MHz for both the FSB and OCZ memory and a CPU clock speed of 3.42GHz. The result was slightly higher memory performance than the overclocked Blitz but system performance that was essentially identical.
We backed these tests up by also using some slower Kingston KHX11000, which ran at 1,260MHz instead of the 1,520MHz we saw with the super-fast OCZ. The difference in performance was absolutely negligible, which backs up the findings in our recent DDR2/DDR3 memory round-up.
At this point it occurred to us that the QX6850 might be the culprit as it's not much of an overclocker so we plugged in a Core 2 Duo E6700 that runs on a slower 1,066MHz FSB. We were able to overclock by 20 per cent to an FSB of 1,280MHz with the DDR3 OCZ memory which was rather disappointing as we're used to seeing Core 2 Duos that shoot at least 30 percent past their standard clock speeds.
On this showing there is no benefit in running astronomical memory speeds on a Core 2 processor, but we already knew that. The benefits of running CrossFire are already clear provided you can stand the hassle, expense and noise. Let's face it, if you want a superb experience you run a single GeForce 8800 GTX.
Having said all that it's very early days for X38 and as we figure out its wiles and ways we may well change our opinion of the new chipset, especially when PCI-E 2.0 graphics cards come to market and 45nm Intel processors hit the streets.
For the time being we're unconvinced by Intel's X38 chipset and DDR3 memory but Gigabyte has done a decent job with the GA-X38T-DQ6 and it looks like it could be future-resistant for a year or two which is pretty good going in this game.