i think you have the wrong idea about what overclocking is. You posted earlier on trying to overclock a 128mb GFX card to 256mb, and u got the response that you cant because that is adding memory which you cant do. Now you want to "overclock" 2gigabytes of memory to 2.5 gigabytes of memory, and this is not possible. Overclocking increases the speed of things, you are adding memory to things you cant add memory to.