Please tell me some Ati video Cards?

Hello.I don't know how Ati radeon hd series works I just know the geforce cards.....So can you tell me all Ati graphic cards that has 512mb or more, 256bit or more, and GPU core speed from 600MHz up.Thank You!|||just use neweggs sorting tool for vid cards, they go into extreme detail, you don't have to buy there but i recommend you do if you end up shopping online.|||http://www.pricewatch.com/video_cards/