I know its a graphics card problem because this game requires 64mb and my iBook only has 32
:?:
First, there's no way you're going to get 1.5GHz out of that CPU, and you would be extremely lucky to get 1.2GHz. I doubt that it's possible.
Second, yes, it will involve soldering, and there's no guarantee of success.
Third, given that the GPU failures are at least in part caused by heat, pumping extra heat into that machine is a really bad idea.
Fourth, given what you say above, why are you even bothering?