Well I think when he used that word 'conflict' it was not a good representation. I could be wrong though. As they, Nvidia and ATI, are both supported by the PCI-Express slot on both machines. To the best of my knowledge.
What I would like to know and I think he would too is would it just be better then to use a ATI card x600,x700,x800,x850 etc than to use Nvidia card. Since the documentation, from what I understand here, supports both but recommends ATI cards.
I have read here also though to get the 6600gt over say the x700pro, since it performs better, evidently regardless of the ATI card recommendation in the documentation. Is that a fair statement?
I will next week be purchasing one of the two and I am still not sure which. I am leaning toward the 6600gt now after reading some on it. But I don't know if any retailer (only 3 I canthink of are Best Buy, Circuit City and CompUSA) in my area carries a 6600gt PCI-E card and I DON'T want to wait I want it all the same day lol. I have checked online and none of them have them it seems, or are out of stock heh. Plenty of x700pro's though. Can't find x700xt's in retail stores though :(.
Good Luck to us both btw!