What you have to focus on is how fast the cpu sends the data to the gpu. Ram plays an important role because the faster it can send instructions to the cpu the faster your cpu can send data to the gpu. So lower latency faster mhz is better if you had to decide between 4gb and 8gb. Dual channel ram is optimal. 8gb would give you better overall computer performance in different applications because the OS eats alot of RAM even if most of it is cache. 8gb is optimal for win7 and up.