I am using Windows 10 64-bit that was a free upgrade from win 7 ultimate also 64-bit. I was using 3gb of ram and upgraded to 4gb, but task manager says that only 3,2gb is usable and i tried msconfig maximum memory but didn't work. I also checked in the BIOS that it was there, and it was, my CPU is a Q6600 so there isn't any integrated GPU problem, and the board is an Asrock G31M-S with p2.10 bios. Performance Monitor says that 833Mb are dedicated for hardware.