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Question: Which Memory speed matches the FSB?

Forum Motherboards & Memory : Memory - Question: Which Memory speed matches the FSB?

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I have been searching google as well as various forums for the last 2 hours, I cannot find a straight answer. It's probably a dumb question but here goes...

What memory speed do I need to match an Intel Core 2 Duo E8500 (2 x 3.16 GHZ) 1333FSB - 6 MB?

I've been baffled by articles that try to explain dividers and what not, all I want to know is the speed which matches the processor.

If someone could answer in the most basic terms. Eg. 1333FSB can use a memory speed of X. I would be most grateful.

Any background info on which speed to choose also would be much appreciated.

Many Thanks

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667Mhz which is pc2-5300, ill edit in a few minute to explain a bit more (done)

First you have to divide the FSB of the CPU by 4 to get the real FSB (since it does 4 cycle every clock or something like that). So the FSB will be 333.25.

Then to find matching RAM, you must multiply the FSB by 2 (because it's DOUBLE data rate aka DDR) so you get 666.5, so 667mhz to get a 1:1 synch.

But you could always run it unsynched and use pretty much any ram speed higher than 667mhz.

Message edited by BigBurn on 06-19-2008 at 12:03:09 PM

Reply to BigBurn

The Front Side buss is 4 operations per cycle - so your 1333 is actually 333 x 4

Memory runs two operations per cycle - 333 x 2 is 666

As far as what RAM to buy: If you are not overclocking, then all you need is DDR2 667. If you *are* going to overclock, decide your target Front Side Buss speed and buy memory that runs at the proper speed for your target.

------------------------------ Which Chip? Well, it depends on which set of thieving b@stardz you choose to support: The ones who use insider trading to enrich themselves while running their company into the ground, or the ones who illegally pay vendors to not support the first group.
Reply to Scotteq

Many Thanks, this was exactly the information I was looking for.

Reply to Quizling

Sorry to hijack this thread , but there wont be apoint making a new thread since its related.
I'm a noob at this intel stuff , so what is the point of running 1:1 ratio or whatever. So if my E7200 is running 1066 i have to underclock my 800 ram to 533 ?

Message quoted 1 times

Reply to Xternal

Xternal wrote :

That would give you 1:1 yes..but it's not necessary.

------------------------------

E6300@3.2ghz 1.32v | Gigabyte P35-DS3R 1.0
4x1GB C5@900Mhz | 8800GT
Reply to monst0r

x: it's just that you won't see any significant performance increase by running the memory bus any faster, since all data to/from the RAM has to go through the FSB as well. If you don't match the FSB and memory bus data rates, one will bottleneck the other.

------------------------------ e2160@3GHz: OCing my way to Ubuntuland!
Reply to Mondoman

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