Wayne, first of all do you have an AMD 2000+ or a 2200+?
I did a little math and came up with the following numbers.
An AMD 2000+ should run at 133MHz FSB * 12.5 multiplier = 1662.5 MHz or ~1.67GHz
An AMD 2200+ should run at 133MHz FSB * 13.5 multiplier = 1795.5 MHz or ~1.8GHz
If you want to maximize your chip's performance, increase the FSB speed back to normal. The Front Side Bus is the bottleneck between your processor and the RAM. The lower the FSB number, the slower your computer is going to go. If you're running your FSB speed at 100MHz, you have reduced your processor's ability by 25%.
To answer your question about the crashing. Every CPU is a little different, and some processors are capable of better performance than others. Even if you had two identically marked chips produced from the same factory, one would probably do better than the other. It sounds like your friend got a better chip than you did, thats the luck of the draw.