memory fsb for cpu?

[compfreak999]

if you have a

400fsb
533fsb
800fsb

refering to p4, im not 100% sure what i know if accurate. cuase dell uses pc2700 for their 533fsb but my friend says pc2100 for 533fsb is ok, so im confused.

 

[ggnl]

PC2100 = 133 mhz
PC2700 = 166 mhz
PC3200 = 200 mhz

Intel's fsb is quad-pumped so it is equal to 4x ram speed. 4 x 133 = 533. So you would need PC2100 for 533 fsb and PC3200 for 800 fsb.

 

[JackHawksmoor]

My i845PE board runs PC2700 with a 533mhz FSB. So I guess that's actually asynchronous? I've never really thought about this before, but I wonder if I'd get better performance underclocking my RAM...