While the 2200 on the Sempron doesn't indicate it's actual clock speed, it is a performance indicator. That is to say it should perform roughly the same as a P4 2.2GHz. Same goes for all AMD chips.
If you want performance comparisons, try sites like Tom's Hardware and Anandtech. Your particular selection in hardware will cause results to vary, but you can get ballpark estimates.
Of course clock speed is only one of about four things that determine overall performance of processors. Without getting into a lengthy discussion, suffice it to say that Intel chips are better if you do a lot of high end gaming, video encoding, or similar multi-media type ventures. AMD chips are better at virtually everything else. The Athlon64 should actually be just as good, or better, than the P4 at those multi-media tasks as well.
I know that i have a p3 processor that is 450mhz's
How can I tell what the processor speed is for the
following? amd sempron 2200 ,celeron 1.8ghz?
How can a person compare p3, or p4 processor's and
mhz's with these other processors?
Is there a website that compares them?

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