This is a pretty laughable basis for comparison - anyone with more than a trivial knowledge of GPUs knows that the largest bottleneck is the bandwidth between s

This is a pretty laughable basis for comparison - anyone with more than a trivial knowledge of GPUs knows that the largest bottleneck is the bandwidth between system memory and GPU memory, and you are always supposed to design your program with this in mind. Doing a trivial benchmark like taking the sin of one number is not only a pointless operation to attempt on the GPU, but not even a good benchmark of real world GPU applications. GPUs are only good at certain things, and tend to rely on producing data on their end (procedurally), or working with the same set of data over thousands of frames or instances. If you took the sin of the results recursively, and did this a million times over, the GPU would blow the CPU out of the water. What you are claiming is like saying that one CPU is faster than another because one reads from memory and the other from the harddisk.