ihog :
The only way to know is to try.
Or do some research, reading, and learning... and not fry things to learn
RAM performance is nil impact on APU/OnboardGPU. Yes it helps, but no where near what i think you are expecting or trying to get. No matter how fast you OC the RAM, you will be limited by the communication channels. This is controlled by the Northbridge BCLK. and OCing this is not for the faint of heart or for those who are new to OC. In addition, messing with the BCLK affects EVERY part of your system = stability issues possibly and heat issues. DO NOT ATTEMPT unless a)know what you are doing b) have a cooling solution in place. That means not stock.
An $80 GPU card will give you better performance than trying to OC ram.
Incidentally, can't really even answer your ram OC question without knowing EXACTLY what model of RAM you have anyway. Kinda important piece you left out... But either way, really is rather pointless with out increasing speed of communication channels