FSB/memory speed question

[BF04]

I see FSB: 533/400MHz
this is for a socket 478 P4. Im not real familiar with Intel stuff. Now I see Intel FSB 1066, does the memory still only run 400mhz ie (3200).

Just trying to get a quick understanding.

Thanks

 

[Lithan]

I believe ddr2 has been speced higher than 400, but ddr1 I dont recall anything over 400 ever being accepted as a standard.

 

[Corsairpro]

there are 2 buses when talking about the path data travels from the RAM to the CPU

The FSB or Frontside Bus IIRC is the bus between the memory controller and the CPU. On a 533FSB CPU (a P4b) for example, it ran on a 133MHz bus that transmitted data four times each clock, yielding the 533FSB figure (133x4). On an 800MHz FSB CPU (P4c / e), the FSB is actually a 200MHz bus that transmits data four times each clock.

The second bus is the memory bus between the memory controller and the RAM. In the case of the P4c/e with an "800MHz" FSB, the RAM actually runs at 200MHz and transmits data two times each clock. This yields 400MHz effective.... which also explains why you should run in dual-channel mode. This gives you two memory buses each running at 400MHz effective or 800MHz total... which matches the FSB of the CPU.