More information needed. Where are you getting this information? Please tell us if the info is coming from the proerties for your PC or is it from benchmarking software of some sort.
Also, what temperature is your CPU running at idle and under load?
Use Everest to determine if your CPU is throttling.
Come back to us with the info above.
Incidentally, googling 'pentium 640 running at 2.2' mostly returns the comparison between your P4 chip and similar rating AMD processors running at 2.2ghz. Are you absolutely sure you've put an Intel chip in there?
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