I think this only happens when you play on high resolutions like 1920x1080 then you have AA on...Although I do wonder what happens when you play a game that uses more than 768 mb of VRAM but still less than 1 GB. I would think they start evening out quite a bit and maybe the 4890 could pull ahead.
wow $70 really? that's a good deal... here in our country it still cost to an equivalent of $125 second hand...How much cheaper is the 4890?
I picked one up on CL for a nephew for 70 bucks...