Below is a chart TH put together recently, gives you an idea of the real world performance ranging from past and present games and even 3d bench mark scores thrown in for good measure, all this is added up and put in one single chart.
look where the HD2900XT 512 ends
An X1900XT 512 would slot between the X1900XTX 512 and X1950XTX 256

The HD3850 has always looked good on paper buddy
Also catalyst drivers are still struggling with anti-aliasing, if only they could nail it like they have with crossfire on current drivers.
look where the HD2900XT 512 ends

An X1900XT 512 would slot between the X1900XTX 512 and X1950XTX 256

The HD3850 has always looked good on paper buddy

Also catalyst drivers are still struggling with anti-aliasing, if only they could nail it like they have with crossfire on current drivers.