You are incorrect sir, far more than 5% off.
This is a SLI score on Intel with a pair of 7800GT's. CPU and GPU overclocked. A single XL scores higher than that.
http://service.futuremark.com/compare?3dm05=1473121
Same cards on AMD will score over 10K.
Its not just SLI, the mobo in general in junk. Yes it works and runs SLI yet sucks hardcore. You would be far better off with a single X1800XL or XT on Intel.
The memory timing used on the Intel rig (crucial memory) was 5-5-5-15 @ 200FSB on the cnet review. I dont think I could have found worse memory. I am willing to bet they used 2-2-2-5 timing on the AMD.
The reason why the AMD timings are so low is because it uses DDR memory and not DDR2 memory. Besides, even though you could use timings of (about) 3-3-3-8??? (dont not sh!t about DDR2, but it sounds about right), the performance increase wouldn't be noticable to the naked eye, and it might get a few more "points" on a benchmark. And as other people said, the perfomance gains/looses would be +-5%, nothing too big.
I hear everyone talk about how Intel delivers the best price to performace ratio. Now, I know they have the cheapest dual core chip, but AMD's cheapest dual core chip is ONLY $77 MORE!!!! So I ask you this, why not spend $77 more on a better performing, cooler, better overclocking, just plain better chip.
(I just checked the price on Newegg, it does not include S+H)
Now I ask my self again, which chip is a better "bang for the buck", I would say AMD, even if it is $77 more. Thats $77 more for a bit more quality.
Don't even get me started on the "Bang for the Buck" of S939 Opteron Processors, they OC like MAD!!!111!!! (and they are MAD cheap too).
EDIT: I was reading the quote, and what about a single 7800GTX, instead of a X1800. Would that be ok too?