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Old 09-03-2008, 03:56 PM   #1 (permalink)
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Default Memory speed

Forgive me for a noob question. I've searched and can't find a specific answer, but I'm sure you guys know the answer without thinking!

I'm building a system (duh!).

FSB = 1333
Processor = E8400 3.0GHz Wolfdale
I am not planning on overclocking.

How do I know what speed memory to get?

does the memory run at the FSB speed, so I should be getting 1333Hz? or, as I've heard from word of mouth, I should get 1/2 that? or what? and WHY?

thanks in advance!
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Old 09-03-2008, 04:00 PM   #2 (permalink)
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Default Re: Memory speed

CPU's use quad data rate, memory uses double data rate. So in theory you should buy memory that is half the speed of the cpu. That being said, just buy some low latency ddr2 800. 4-4-4-12 ddr2 800 is the easiest to get for a good price.

Also, overclocking the FSB to 400 on the e8400 should be a breeze.

FSB = 333
DDR2= FSBx2 (assuming you run memory linked, heh i'm going to confuse you more now )
CPU= FSBx4

That help?
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Old 09-03-2008, 04:02 PM   #3 (permalink)
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Default Re: Memory speed

So any memory speed above 1/2 that of the FSB will work fine and will not "overclock" the memory?

fantastic info - thanks so much!
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Old 09-03-2008, 04:04 PM   #4 (permalink)
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Default Re: Memory speed

The FSB of the CPU is divided by 4, while you divide by 2 for the RAM. For example, if you overclocked the E8400 to 3.6 ghz (FSB of 1600/4=400), it would be running at a 1:1 ratio with DDR2 800 RAM running at stock speeds.

edit: too slow
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Old 09-03-2008, 04:06 PM   #5 (permalink)
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Default

Fantastic info, guys! and fast replies! thanks so much!

Ok, I hope I don't wear out my welcome!

Next question: which is better:
Low CAS Latency OR Dual Channel?

In other words, if I can get 4-4-4-12 single channel or 5-5-5-18 dual channel - which would be more efficient?
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Old 09-03-2008, 04:50 PM   #6 (permalink)
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Default Re: Memory speed

Its all dual channel. Get the 4-4-4-12
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Old 09-03-2008, 04:56 PM   #7 (permalink)
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Default Re: Memory speed

Ok, but I'm confused why newegg lists them separately as dual channel and then just singles. they have dual channels that come in packages of 2, but the others are in singles. they don't have to be matched to be dual channel?
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Old 09-03-2008, 05:02 PM   #8 (permalink)
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Default Re: Memory speed

They dont have to be matched. But matched pairs usually perform better. If you bought 2 singles, and ran them in the right socket, they would still run in dual channel mode. But yes, its usually best to buy them in matched pairs.
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Old 09-03-2008, 05:07 PM   #9 (permalink)
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Default Re: Memory speed

But lower latency memory will perform better than matched pairs?
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Old 09-03-2008, 06:05 PM   #10 (permalink)
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Default Re: Memory speed

being a single stick doesnt make it single channel. its still dual channel ram, you just have to run it with another. ie if you have only one stick it will run in single channel.
buy a low latency ram that has an even number of sticks.
in other words, if you want 4gb, buy a 2 x 2gb kit. if you want 2gb, buy a 2 x 1gb kit.
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