Your memory will work no problem. not sure on your CPU fan, stock cooling is quite good on the opterons. Guys have gotten 3.0GHZ on those opterons with stock cooling.

The SLi is cheaper. Infact you can get almost identical performance to two x850's with two 6800GS's. And the GS's are cheaper. $279 Canadian @ Infonec. I'm getting my X850's from a friend. And I will watercool them, and overclock the piss out of them. But stock to stock I believe theres hardly any difference between the X850's and the 6800GS's.

The only thing is, I'm not a fan of NVidia, they're tech support or their quality.

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