Sorry to say but it does not matter. The performance of Intel HD gfx is so poor that it is only good for showing some image, play movies at 1080p. Do not expect more. You can play extremely old games at low res but not newer ones.
For gpu only vram is not all. Its processing power is also very important. It is like another small cpu,ram setup like a small computer dedicated for parallel computing unlike the way a cpu works. So if you have only intel HD gfx and say it is 8GB (by any magical way) you can not play recent titles.
However AMD APU has much better igpu than any Intel compared to even a i7. but a apu is decent at low resolution gaming