pok125 said:
I dont know much about them but usually the bigger number the better right? Altho the x1900 is cheaper than the x1800?
Ahh if only life were so simple eh?
It depends what you are after I suppose.
If you are planning to have 2 cards running in crossfire mode, either now or in the future, you have to get the X1900GT (as the X1800s don't support crossfire).
If however you are wanting pure processing power from a single card then it is mainly the letters following the model number that you want to look at:
XT > GT > Pro > others
This is basically due to the XT series having faster core clock speeds (625MHz as opposed to 575MHz in the GT models) and RAM clock speeds (1500MHz as opposed to 1200MHz in the GT cards).
Obviously the model number plays a part, so X1900XT > X1800XT > X1600XT as they tend to indicate the number of pixel pipelines (basically the number of pixels which can be processed per clock cycle, and the higher numbered cards tend to have more).
As you can probably see it's not exactly a straightforward process, though to simplify I would tend to advise that for the same brand the higher the RRP, the better the card, thus for a single card X1800XT > X1900GT
edit: see
HERE for a decent comparison chart
