check the bios options
most of the time you can choose between following options:
8/16/32/64/128 MB shared
maybe 8 and 128 isn't available for you, depends on the mobo
so, it's not possible to choose something like 12 or 48,..
would you post please, why you need more video ram?
maybe you can better put an AGP/PCI-e GFX-card with 128 MB in your system.
if you mean the increasing the RAM on your AGP/PCI-e card, you can't
unless you've got some old matrox card, some of them can, but the it's cheaper to plug in a decent new card.
reply to Comptia_Rep:
correct me if i'm wrong but the aperture size ain't the memory for the gfx card, it's the RAM used between the gfx memory and the swap file on the drive.
but if you use onboard graphics, the graphics memory and de aperture size both will be the computers RAM.
ROFL You have no idea what his computer is do you? PCI-e? C'mon at least read his posts before you give advice.
Anyways, It looks like you have an Aristo motherboard, of which I can not look up at work (foren). And talon was correct, Apature size is not the word I was looking for, and I cant remember what it is. Realisticly, you most likely can not change memory usage on that board, and if you could, it would not be significant (options should be 1,2,4,8). If that board had an AGP slot, get an older AGP card, if not get a PCI graphics card to improve your performance.
Otherwise, play around in the bios untill you see something related to the graphics (card) and change the value higher.