Originally Posted by
Xc3
this really looks like a driver problem yes, i had some trubbels with my 4870 saphire aswell tho i have the 1gb version:> but anyway with such important hardware change as a graphic card i recommend reinstalling ur OS just 2 get rid of every old graphic driver that could lure in ur computer (if you unistall a driver via clicking uninstall in windows own tool thing its known that it wont remove the driver completly and it will interfair later) you can try a program called "driver cleaner aswell" work quite well if you dont wanna reinstall ur OS and be 100% sure:P AND a very important thing! espacially with saphire card imo, you gotta flash ur bios to the newest version.
hope this helped