How does FSB and RAM speed work?

[Mr_Threepwood]

Ok, I just wanted to ask why on some chips, like my p4 3.2 ghz with 800 mhz fsb, you need to get 400 mhz ram speed. I was originally under the impression that you need to get ram speed to match that of your FSB, which would make sense. Can someone explain?

 

[Elbatrop1]

I think this will hold the answers that you seek

 

[Apokalipse]

PC3200 RAM actually runs at 200MHZ, not 400. but it does twice the work per clock cycle as SDRAM, so people often call it 400MHZ even though that's not the case.

and your FSB is split up. it is actually 4 x 200MHZ. it means there is room for more RAM disks.

Intel originally made the 800MHZ FSB because they wanted people to use RDRAM, which was faster, but much more expensive.
RDRAM never really took off, it faded away against the much cheaper DDR, which became the dominant RAM in the market.