i searched a lot about both the champs but mostly found that gtx 590 slightly beats radeon 6990.i dont know why but i found that radeon 6990 is more power packed for ex 4 GB VRAM(helpfull on huge resolutions),Unified shader processors 1536x2 in 6990 and 512x2 in 590,texturing units 96x2 vs 64x2,effective VRAM frequency 5000 vs 3141 for 3d and 600 vs 270 for 2d etc.After winning most of the hardware championships our boxer 6990 is loosing against 590.Let me know why? is there any tricks played by nvidia for better optimization of games sponsored by nvidia or really ATI is a looser(I DONT THINK SO).this discussion is going to help a lot of people to choose between them.so lets ring the bell.
thnx in advance.
If you are at all interested in doing any bitcoin mining, the HD6990 is the only way to go; no nVidia card mines enough to recover even the power cost. If it is strictly for games, I'd be more inclined to choose nVidia because I don't like the noise of a GPU fan howling at me.