This is my personal 5870 test with popular benchmarks from guru3d and few games so you can compare this results with your rig at home if you are thinking about upgrade...
2 rigs, first AMD based, then Intel based
1920*1200, all details are highest available in options without AA
AMD Phenom II 965 C3 4.0GHz
Big Typhoon
Gigabyte 790FXT-UD5P
2x2GB Dominator GT 1866C7 @ 1600 6-6-6-18 1T
1TB Seagate 7200.12
Corsair TX 850W
XFX 5870 XXX Edition 875/1300
Resident Evil 5 Variable DX10
http://img690.imageshack.us/img690/1...1562610.th.jpg
Resident Evil 5 Fixed DX10
http://img696.imageshack.us/img696/5...1483191.th.jpg
Street Fighter 4
http://img31.imageshack.us/img31/130...chmarcp.th.jpg
Call of Juarez DX10
http://img6.imageshack.us/img6/9243/...2120402.th.jpg
Devil May Cry 4 DX10
http://img33.imageshack.us/img33/118...hmarkdx.th.jpg
Stalker Call of Pripyat DX11
http://img31.imageshack.us/img31/570/stalkerc.th.jpg
Crysis Warhead Gamer DX10
http://img31.imageshack.us/img31/249/crysisgamer.th.jpg
Crysis Warhead Enthusiast DX10
http://img690.imageshack.us/img690/5...sisenth.th.jpg
FarCry 2 DX10
http://img171.imageshack.us/img171/1970/farcry2.th.jpg
World in Conflict DX10
http://img6.imageshack.us/img6/4674/...3010364.th.jpg
Heaven DX11
http://img215.imageshack.us/img215/7192/unigine.th.jpg