My X850XT gave up on me today. I cannot RMA due to modifications, so it's $500+ shot to hell. Now, would another X850XT outperform SLI'd 6800GT's? Or, even better for me, that new Gigabyte dual 6800GT card? I'd prefer to stick with one card, but I don't know if I can foot the bill for a 7800 series. I'd also prefer a factory "quiet" solution if that is possible, so I don't run into the problem I'm facing now (needing an aftermarket cooler, etc). Thanks