Memory, motherboards, and processors

[Kane040]

Okay, lets say i want to buy an 800 mhz motherboard, and i bought 512 mb of PC 3200 DDR400 memory, and on the back of the box it says "systems running 800MHz FSB will run at 400MHz". Does this mean i shouldnt bother buying a 800MHz processor, and motherboard?

[Cricket]

Originally posted by Kane040 Okay, lets say i want to buy an 800 mhz motherboard, and i bought 512 mb of PC 3200 DDR400 memory, and on the back of the box it says "systems running 800MHz FSB will run at 400MHz". Does this mean i shouldnt bother buying a 800MHz processor, and motherboard?

There is a lot of confusion about what speed a system really runs at...we have both the Intel and AMD marketing departments to thank for that.

What you have to do is look at what speed the motherboard's FSB (Front Side Bus) is really running at to get a good idea of what's really going on.

On an Intel P4 system, the P4 itself has an internal bus speed of 800MHz. The PC3200 DDR RAM runs at 400MHz. But the motherboard FSB is really running at 200MHz. What's happening is the P4 is using a Quad Pumped technology that allows instructions to be read 4 times per clock cycle instead on once per clock cycle. So multiply the motherboard FSB by 4 and you get 800MHz. Same goes for the DDR RAM...DDR or Double Data Rate RAM reads instructions twice per clock cycle, so you multiply the motherboard FSB by 2 and you get 400MHz. But the motherboard FSB is still only running at 200MHz.

Confusing? Yes...but that's just how it works. The PC3200 (DDR400) is actually the correct RAM to use in a 800MHz P4 system. Just remember that the motherboard FSB doesn't run at 800MHz...it runs at 200MHz.

Cricket

[bailey]

right
and that still is confuseing me a lot of times too

[Kane040]

Thanks for the help, its really appreciated. Oh, and my tight budget thanks you also