im having intel pentium dual core E2160 processor @1.8ghz. and a 2gb ddr2 ram @ 667mhz and the motherboard is GIGABYTE GA G31M-S2L. the motherboard has one PCI express x 1 slot and one PCI express x 16 slot. the chipsets are G31 express chipset (north) and ICH7 (south). now how can i know what are all the graphics cards compatible to it. graphics cards have core speed and memory speed. what should be these values for moderate gaming. do i get a driver disk and few games on purchase of graphics card. what is the use of graphics memory. what will be the use if it is a higher value like 1gb.