I'm pretty sure modern GPUs are pipelined and cached. The important tidbit is that CPUs find parallelism where the programmers didn't specify any. CPUs are "ou

I'm pretty sure modern GPUs are pipelined and cached. The important tidbit is that CPUs find parallelism where the programmers didn't specify any. CPUs are "out of order" machines, spending a fair amount of energy and internal storage (the ROB / reorder buffer) to execute out-of-order, and then place all the results back in order before the programmer notices. GPUs, instead of being configured to find parallelism, innately assume that the programmer laid out parallelism for it ahead of time. GPUs can only work with a massively parallel language (OpenCL, DirectX HLSL, or CUDA) specifying thousands of parallel work units per line.