How to determine processor speed

Click on Start point to programs, accessories, system tools and click on system information.
The system information window will appear. There, in the Sumamry should appear your processor type and speed.

The speed, type and other processor information should be displayed by the POST on startup.

Alternatively, SiSoft Sandra or other system test utility will give you this information. One other method is to remove the lid of the computer, and look at the cpu itself. It may be that your BIOS reports a given CPU at a particular speed, but in actual fact you have a very different scenario. One of my customers PC's reported a Pentium-S 150Mhz in BIOS, but actually had a P133 chip, which had been overclocked. The manufacturer was selling both P133 and P150 variants of this particular machine, but the P150 was an extra ?49. It seems that in this case, the client was robbed of his ?49 by the manufacturer overclocking the CPU. I actually managed to 'upgrade' the machine with a genuine P150 and then overclock it to 166Mhz with no instability!!

Remember also that Cyrix Processors also had different clock speeds from their actual PR rating, so a 686MX cpu might be clocked at 133Mhz but display a 'speed' of 180Mhz in the bios.