Windows actually control the amount of RAM that is used for internal graphics. The setting in Bios (if available), just guarantees that the minimum amount is used for graphics. So, for instance, if the OS determines that 1Gb is needed for graphics, that's what is allocated. In practical terms, I've never seen an difference if the minimum was set to 128, 256 or 512Mb. If you're running a game, just be sure to close down all other programs.