All new Celerons are Socket 370, but it is possible to get up to a P3 1GHz in slot1 form with a 100 MHz FSB. It is hard to find the 1GHz 100MHz FSB models though. More likely, you will find P3 800's in a Slot1 100MHz form. So, IF your board supports coppermine P3's, you can go from a P2 450 to a P3 800 for around $150. Right now, as a matter of fact, Mwave (
www.mwave.com ) has the P3 1000 Slot1 for $220, and the P3 850 Slot1 for $165. Both are 100 MHz FSB. Of course, for that kind of money, you can buy a new socket 370 MB and a Celeron. I've got a P3 800 Slot1, and if I had it to do all over again, I'd get a socket 370 MB and a Celeron. My brother uses nothing but Celerons, and his benchmark numbers in every area are just as good as mine, or better in a lot of cases. (Of course, his are overclocked to 100 MHz, or very near that.) The newest Celerons already run at 100 MHz, so that isn't even an issue anymore.