I want to choose a videocard for my pc to work properly with HD-movies and video editing.(Premiere CS3) I have a: Processor: E6750 Mobo: GA-P35C DS3R Memmory: G.E.I.L 2x 1GB 800Mhz I am confused wich one to take rather 512 with lower speed or 256 with higer speed. Or should i choose something else?