I took a fourth year computer architecture course that can be summed up as "clock speed has nothing to do with computing power".
Yeah, no kidding. The old quote (Mark Twain?) "there are three kinds of lies: lies, damned lies, and statistics" is really true when it comes to computer performance metrics. Here's a new favorite of mine from Dilbert: "A misleading benchmark can accomplish in minutes what years of good engineering could never do."
It's funny that I'm looking at a problem that, when executed on an FPGA poking along at 200MHz, I expect it to outrun a ~4GHz microprocessor easily.
The real, ultimate metric is this: does it run my program in a time period that meets my requirements?
-j