Ordered an Asus P5N32-E SLI PLUS.. but now I'm confused!

[tooner]

Got one of these bad boys coming to me but I'm not sure what ram speeds to use.

Do I go for pc8500 5-5-5-15 or pc6400 4-4-4-12?

I don't intend to overclock but I have been unable to find any information on what RAM speeds this board supports.

Does anyone know if the board will support pc8500 without overclocking?

Thanks in advance
tooner

 

[Alsone]

I'm confused as to why you want such fast ram.

Your ram will only run as fast as your FSB so if you've got a 1066mhz FSB, the ram you'll need will be 667mhz in dual channel.

667mhz x 2 = 1333mhz x 5:4 fsb ratio = 1066.4 mhz

PC6400 (800mhz) will support an fsb of 1600mhz at 1:1 so should be more than enough especially if you're never going to overclock as it already gives you an overhead.

I've got an E6600 overclocked to 3.0ghz and my pc6400 is only running at 667mhz and thats at a 1:1 ratio!

PS I have one of these boards and they're sweet.

 

[oldgreyhead]

You could download the manual from the Asus site.

 

[tooner]

Ah thanks alot. I didnt realise that dual channel meant i needed half the speed. Doh! Thats great news then. I've ordered a E6600 also so I was thinking along the lines that if my FSB is 1066 then I'd get best performance from ram that ran at the same speed.

I wasn't planning on overclocking but if you can get 3ghz out of an E6600 then I might have to change my mind on that issue

Cheers!
tooner

 

[tooner]

That ram costs around $250 in UK it seems. I usually go for crucial ballistix. Think these will do the job?

 

[tooner]

Thanks! Will give it a go.. fingers crossed

 

[Alsone]

Ah thanks alot. I didnt realise that dual channel meant i needed half the speed.

Well theres some argument on here elsewhere as to whether or not its the dual channel or Intel quad pumping that leads to you only needing 667mhz. The Tom's overclocking guide says Dual Channel which is what I understand to be responsible as the FSB is the bus link between the memory and CPU and not the memory itself. So whilst the bus is quad pumped, I understand that the memory is a different entity and reaches its speed through double data rate (x2) plus dual channel (x2) = equals 4x.

However, how its reached its academic because the fact is if you have dual channel then 667mhz ram on an Intel system with give you a 1066mhz equivolent speed with a FSB: Memory ratio of 5:4, so no need for anything faster! As pc6400 is 800mhz ie already over speed, its more than you need so will give you some headroom for the future.

This is my board as reported through cpu-z, you can see my pc6400 is only running at 667mhz (333mhz actual core speed) but I have a 1:1 Memory to fsb ratio through running my bus overclocked at 1333mhz (3.0ghz on processor).

If you don't overclock then as I said above, you'll have 667mhz at 5:4.

PS on this motherboard stick to memory ont he Approved Vendors List only as Asus won't guarantee it to work with any other memory as its choosy. I'm using Kingston HyperX in mine, but if your Ballistix model is on the list it should be fine.