I;ve been playing oblivion at 800x600 w/ hdr on . after a while it freezes on me or crashes my computer. i have a e6600 gigabyte dq6, 2 gb ddr2 ram, and vanilla evga 7900gt. i thought i'd be able to play this thing on a little higher settings with this rig... is this a hardware defeciency or something else? Please HELP.