This chart gives you the actual price/performance ratio of Celeron and Pentium III CPUs. The green lines show the ratio using the regular clock speed, 66 MHz with the Celeron and 100 or 133 MHz with the Pentium III. Of course you get a greatly increased price/performance ratio after raising the FSB clock.
It's important to know that Intel makes their chip prices according to the core clock speed. That's why a Pentium III 600E (100 MHz) costs the same as the Pentium III 600EB (133 MHz). However, the 600/133 is as fast as a 700/100 or 750/100, depending on the application. I think this shows once again that running a Pentium III at only 100 MHz system speed is a huge waste of performance. Motherboards and RAM for 133 MHz are no more expensive than 100 MHz components; therefore it's advisable for Pentium III buyers to choose a 133 MHz system today.
The story is different for users with a small budget. In this case, just the result counts. I think it's not exaggerated to say that from the price point of view, there is little alternative to an overlocked Celeron with Coppermine-128 core right now. In addition, you can easily upgrade to a Pentium III later.
Again you can see some results missing because those setups did not want to run reliably. I already mentioned that we couldn't get our Celeron 400 to run at 500 MHz or more. Please be aware that this is an unusually negative result, as most Celeron 400 CPUs should easily reach between 500 and 550 MHz, unless the CPU is already older than approx. 18 months.
The below results were achieved by dividing the Quake III frame rate score by the average price spotted at pricewatch.com.