Graphics card guide?

long time no see romu forums, anyways. what are are things i should look for when buying a ati graphics card? What is a good memory interface/type? which is more important core clock, number of stream processors or memory clock speed? i want a card that will run games at playable frames and on good settings and at max res but that will also support a 500w power supply.also is it allays true that the higher number the series is the better the card is?current specs
Mobo:ASUS M4A785-M~intergraded 4200
CPU: AMD athlon II X2 3.0 ghz
Ram:Kingston HyperX 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 1066
OS: Windows XP (for now, planing on upgrading to 7 later on.)

The way I think it works is for any given 3rd digit in the model number, higher digits for the first two is better, eg a 5870 is better than a 5670 or a 4870.

ATI's numbering system confuses me as wellall I know is this a HD 4970 > HD 5670 but HD 5670 > HD 4670

yeah, seeing things like that confuses me too. which is why i wanted to know how to judge the cards by specs.

You can always go to ATI/AMD's main site and check the cards themselves, I think the requirements are listed as well.

Buy a 6850, two if you've money to sink into it.PROBLEM SOLVED