-Now we come to clock speeds. As described before processors are measured in Mhz (Megahertz) which is an expression of millions. A 400 MHz can do 400 million operations a second. Now something that is kind of a bummer about this. Your processor can take a chunk of data and crunch it away fast but when it hits the outside or the internal bus it will only travel at 66Mhz or 100Mhz at this time. So it is getting slowed down. Be aware of this and know that you need a good combination of BUS speed and the Core speed of the CPU. Thankfully technology is getting better and changing rapidly. These speeds will be improved for a better match and fit, so just hang tight.
-Non-Intel processors have adopted a P-rating. This is a rating of a processor in comparison to Pentium processor's. This can be somewhat deceiving and allows for false benchmarks from vendors. Read some benchmarks comparisons before buying a processor and talk to people who already purchased the CPU.
CPU's Clock Speed's 
