I might have to refrase myself. I havent had that many problems with my singlecard, except for some blackscreens and lack of performance with the 10.3 driver etc. But i see alot of people having problems on with ATI crossfire since the 10.6 drivers. By that i mean crossfire with less performance then a single card etc. 10.7 drivers are pretty much useless to people with crossfire.
All in all it seems to me that even though Nvidia cant beat the performance to price of the ATI cards, they are more stable?
Yeah, I haven't had any luck with the newer drivers. But, 10.4 is working just fine for me. Maybe you should try using 10.4. I'd hate to make you spend money that you don't have to.
But if you've tried that and nothing seems to work, you're still not satisfied, then you could go with 2 GTX 470's. Because looking at some benchies seems to show that 2 GTX 460's would be better than a single a 5850. While 2 GTX 470's would be even better than that. So I guess it depends on what kind of performance you're really looking for.
Alextheawesome! (truly a fitting name) thanks for replying so fast!
I have been looking at 2 x gtx 470s but im afraid my Corsair 750 w wont be enough at full load. If the PSU i got is enough im considering going for this setup, but if the PSU is not big enough it will be a very costly affair. 2 x 5850s i know my PSU can handle.
My second concern is that the 2 x GTX 470 will become to warm in SLI. My PCI-Es are close to each other. I heard these cards run very hot.
Well, of the top of my head I don't know how much 2 470's need and it also kinda depends on the rest of your system. http://www.antec.outervision.com/ <--- that's a calculator that can tell you how much wattage you would need. Just imput your components and it'll take care of it for you. But I think you should be safe.
As for the heat, they are designed to be able to run hot so that shouldn't be a problem. But if it gets too hot for your liking you can just up the fan speed.