Well lets see
Oh looks like the 5970 is kicking the GTX580 ass in "most" of those games, CF scaling looks fine to me.
Maybe they are bias, yawn.
yep again the 5970 is beating the GTX580 over all, seems to scale just fine in most of those.
BUT @ 2560x1600
So in conclusion the HD5970 is faster @ 1080P and below and the 2GB version of the 5970 struggles at higher resolution due to ram limitations, ALTHOUGH the benchmarks may not reflect this.
There is the 4GB version of 5970 and I assume it performs better @ 2560x1600 +