1066 FSB CPUs and DDR2 800 RAM

[coolego1]

Hello All,
I am looking into a new system and am wondering if I get an intel Core 2 Quad with a 1066MHz FSB, will I be able to use DDR2?

The P35 motherboards seem to have 1066/1333 FSBs... Can I use DDR2 800 in these motherboards?

Thanks

 

[cmdrdredd]

Yes you can. The FSB is 266Mhz x4 = 1066 or 333Mhz x4 = 1333. The Memory runs on a ratio so you can run 266Mhz FSB and DDR2-800 if you want.

 

[gardener27]

1066 / 4 = 266 mhz *front side bus all intels are quad pumped so divide the 1066 or 1033 or 800 by 4 to get the mhz
ddr2 800 / 2 = 400 mhz ddr 2 ram is double data rate so divide by 2 to get the mhz

you still have another 134mhz untill you reach ddr800 speeds so you will be fine.

 

[JustaGeek]

With the FSB of 266MHz and memory divider of 3:2 you get 400MHz Memory Bus x 2 DDR = 800MHz.

In my case 325MHz FSB x 16/13 Memory Divider = 400MHz Memory Bus x 2 DDR = 800MHz Memory speed.

 

[coolego1]

Wow, I have no idea what most of that meant, but thanks, I get the idea that it's basically going to work!

 

[RussianSensation]

Originally posted by: coolego1
Wow, I have no idea what most of that meant, but thanks, I get the idea that it's basically going to work!

1066FSB means that DDR2 533mhz is sufficient (for c2d just divide FSB by 2 to get the ram speed you need). So DDR2 800 will just run at slower 533mhz speed assuming 1:1 ratio is selected (the lowest ratio for P35 chipset). 1:1 just means memory and processor are running in sync with one another.

 

[hans007]

because all the intel chipsets support dual channel, the bandwidth just needs to be the same as the bus of the cpu.

so a 1066 bus cpu needs 1066 worth of bandwidth, dual channel that is only ddr2-533 (the only way this isnt true is if you use integrated video, but i doubt you will do that with a q6600) since 533 x 2 is 1066. you only really need higher speed for overclocking.

 

[Upgr8er]

A tag along question:

If one were shopping for a core 2 6750 would one want the less expensive 1333 fsb version or the more expensive 1066 or does it not matter (for use on a P35 chipset)?

Thanks!

 

[cmdrdredd]

Originally posted by: Upgr8er
A tag along question:

If one were shopping for a core 2 6750 would one want the less expensive 1333 fsb version or the more expensive 1066 or does it not matter (for use on a P35 chipset)?

Thanks!

You mean the E6750 vs E6700? That really shouldn't matter once you start overclocking. Both should top out around the same levels. The only advantage to the 1066 model is a higher multiplier which enables you to get high CPU speeds without as much FSB.