Re: which is better
Simply put, the GTX/Ultra are better than the HD 2900XT overall. It's not all about the clocks and available memory, there are many other factors as well.
ASUS A8N32 SLI-Deluxe, AMD Athlon X2 3800+ @ 2.8GHz, eVGA 8800GTS 320MB, 2GB Corsair XMS DDR400, 160GB WD HDD + 320GB Seagate Barracuda 7200.10, AC Freezer 64 Pro, 700W OCZ GameXStream, NZXT Zero :D
I think I've decided to leave... maybe I'll come back sometime.