Gigabyte G41MT-ES2L has the Intel GMA X4500 whereas Gigabyte G31 es2l Has Intel GMA3100 as the onboard graphics chipset. Since you are going to use a discrete card, I guess it doesn't matters much.For the record, X4500 is better than 3100 IGP. The other area where you'll find G41MT better is in terms of memory support. It supports upto 8 GB DDR2 whereas G31 is capped at 4GB.In terms of overclocking G41Mt is supposed to be better again, however I don't think you'll be able to get past 1333Mhz FSB on either of these boards, but having an updated BIOS certainly helps(G41MT again).
