No, GPUs are quite different than CPUs with more cores. They're optimized for Singl-Instruction-Multiple-Data algorithms, in which the same operation is done at the same time to many different inputs (think image or video processing). They do very poorly in cases with complex branching logic.

I know, but isn't that what the OP was asking for? Isn't that an inherent tradeoff? Or: isn't that what Neuromorphic hardware and deep learning are about (ie. composing many relatively simple functions without complex branching/logic)?