What are the best "performance per watt" (measured in MFLOPS/W) for current CPUs and GPU's?
I hear it is near 500 MFLOPS/W for entire computer ( www.green500.org ), but What is the current record for bare CPU or GPU chip?
The November 2011 results from green500.org lists top 1 as 2026.48 MFLOPS/W. Considering that the top-of-the-line ATI Radeon (Radeon HD 7970) does 16473 MFLOPS/W according to http://en.wikipedia.org/wiki/Comparison_of_AMD_graphics_processing_units I'd say that any HPC system that does not use high end GPUs is wasting a lot of electricity. I'd guess that the best method would be to use the slowest CPU possible to still feed the GPU (that is, try to do no work on the CPU, only use it as a fancy IO-processor for the GPU).
Of course, this is the maximum computing power you can get per watt. For a generic HPC system running a program not specifically made for the ATI Radeon GPU, the results will be much worse.