I have core i3 530 on Asus p7h55 pro and 2gb memory. Windows shows 1.85gb. I think the remaining is used solely by the onchip gpu.
Can/how do i increase that amount and extract more graphic performance?
Can do i increase that amount and extract more graphic performance?
Increasing the memory allocated for a GPU has no bearing on the performance. The IGP's aren't very powerful, and adding extra memory won't be of any use.
Have you attempted to use the ASUS utilities at your disposal?
I have one of their laptops and it makes managing overclocking a thoroughly easy task. I would recommend popping open the ASUS utility for your IGP and see what tweaks you can make. Although allocating more memory to the GP itself may not be your best bet, overclocking the IGP may be an option. (Sorry the link is to an -EVO instead of -PRO.)