Is a g-force 7600gs pci-e 256mb faster or better than a 7300gt 512 pci-e with 512mb? thanks
Yes, both. Usually with ATI's and Nvidia's graphics cards, the higher the number the faster the card is.
The amount of memory isn't as important as the core clock, memory clock, memory bus, number of pixel/vertex shaders OR stream processors (graphics cards can't have both), the clock of the stream processors (if applicable) and the type of card (PCI, AGP, PCI-E).
The GeForce 7600 GS should win.
Don't forget bandwidth. After 18/20 GBsec things get quality.
It seems that g-force 7600gs is better.
Head to head:
And here is a chart on how all the cards rank for July 2007