In most cases, the computer manufacturer has already configured the system to use the maximum amount of graphics memory that is possible for your particular computer model. Sometimes you can change these values through BIOS level.
Check with your computer manufacturer if there are tips on increasing the amount of graphics memory for your computer model.
If you are interested in additional information see below:
i can't find any thing i can edit in BOIS , there is just lang and fan and some other things . also if i upgraded the ram will it increase ?!