You can't change the VRAM without changing the grafic card. It's not the same kind of memory as the RAM. The VRAM is dedicated on the grafic card. On some computers that have integrated grafic card to the motherboard, they have dedicated some amount of the regular RAM as VRAM, and then you can change it. On your computer though (and close to every other computer) there's a dedicated separate VRAM, which you can't change. Only thing you can change is the regular RAM but it won't change your grafics. But your computer will still feel faster by upgrading your RAM