Comment Re: Title condradicts summary (Score 2) 144
GPUs are optimized for massive parallelism and can be much faster than CPUs that aren't for tasks fitting them. They can also be much slower if the task doesn't fit them. 500x faster than a normal processor is well within a reasonable speedup range.
But I also agree partially with you - the reason we see such a huge speedup in this case is probably because the CPU comparison point is running badly optimized code. With a few exceptions reports of huge speedups for GPU computing is because the CPU is feed with severely suboptimal code.