FSB rules, but you really need a Canterwood/Springdale to take advantage of the 800 bus CPUs. The 2.4C running in a dual channel DDR mobo at high FSB will whip up on a 2.53B running in a regular single channel DDR mobo.
JD, I got tired of getting yanked around by vendors that didn't have CPUs in stock. I had a 2.6C ordered from one place, I cancelled and ordered a 2.8C from another place, cancelled when I was told it would be another 2 weeks (they told me 2 days at first). So I said "screw it" and ordered a 2.4C from googlegear. I will probably try a different speed CPU in another month if I'm not happy with this 2.4C. I had to get a CPU soon, so I could sell my two old RDRAM systems. I need the cash to help pay for the upgrades and I promised friends these computers next week.