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Memory timings (which to pick)

Last response: in Overclocking
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December 22, 2006 6:07:16 AM

I'm building a new system and need information on what kind of memory to choose.

My system will be built around an Asus P5B Deluxe and an Intel C2D E6600.

I notice that there are different kinds of DDR2-6400 memory available with different timings. Should I pick memory with 5-5-5-12 or 4-4-4-12 or 3-4-3-9 or what?

More about : memory timings pick

December 22, 2006 6:12:57 AM

lower is better, i would suggest this, 4-4-3-8, lowest timings ive seen for PC-6400 @ stock settings. and its pretty cheap.
December 23, 2006 1:04:13 AM

So is it pretty safe to say that if I get 5-5-5-12 PC2-6400 memory from like Corsair then I won't be able to overclock much?
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a b } Memory
a b K Overclocking
December 23, 2006 1:56:56 AM

The response time of CAS5 is slower, it requires 5 cycles to initiate transfer.

Anyway, any PC2-6400 has 800MHz data rate and runs at 400MHz clock, Core 2 Duos run at 1066MHz data rate and have 266MHz clock, so for overclocking you can drop the RAM speed and raise the CPU FSB while loosing little to nothing in memory performance.

Because of dual channel mode, PC2-4300 is fast enough to perform well with stock FSB1066 processors, so any PC2-6400 leaves lots of room for CPU overclocking so far as you keep memory speeds below 800
December 24, 2006 2:17:00 AM

Quote:
So is it pretty safe to say that if I get 5-5-5-12 PC2-6400 memory from like Corsair then I won't be able to overclock much?


Not true...Loose timing actually helps overclocking stability with really negligible loss of performance. I think TH did an article on Ram timings.

My Ram is 5,5,5,15 and Im at 3.5Gig stable...
a b } Memory
a b K Overclocking
December 24, 2006 3:14:35 AM

Quote:
Not true...Loose timing actually helps overclocking stability


You mananged to turn a true statement into a false statement! LOOSENING your timings helps make memory stable when overclocking. That means setting CAS5 for CAS4 rated RAM, etc.

You don't have any room to "loosen" CAS5 in many situations, but loosening to CAS6 would be rather lame.
December 24, 2006 10:09:41 AM

Quote:
My Ram is 5,5,5,15 and Im at 3.5Gig stable...


Just curious...how did you get 15? I thought it was 5,5,5,12.
December 24, 2006 10:13:51 AM

Quote:
lower is better, i would suggest this, 4-4-3-8, lowest timings ive seen for PC-6400 @ stock settings. and its pretty cheap.


Quote:
Not true...Loose timing actually helps overclocking stability with really negligible loss of performance.


The above two quotes have confused me. They both appear to be saying the opposite thing.

So is lower timings better like apt403 says? Or is "loose" timings better as deadlydude suggests? Please clarify! Thanks.
December 24, 2006 10:24:15 AM

Quote:
Not true...Loose timing actually helps overclocking stability


You mananged to turn a true statement into a false statement! LOOSENING your timings helps make memory stable when overclocking. That means setting CAS5 for CAS4 rated RAM, etc.


This is a true statement, tigher timings are always better @ stock, but when your oc'ing if you loosen the timings it puts less strain on the ram so its more stable, so you always want to go with the tightest ram you can, that way, if you decide to lossen up the timings the performance loss isnt as bad.

like lets say you have some 5-5-5-15 ram, and lossened it up to 6-6-6-16, then compared it to ram with timings lossened from 3-3-3-13 to 4-4-4-14, you turned the timings up by the same amount, but the stuff with tighter timings to begin with comes out ahead. there are other reason for buying ram with tighter timings, but i wont go into there right now.

does that make any sence? im kinda tired right now. :?

the info is valid, but the wording might be a little off. for the past 6 hours ive been pounding coffee and listening to envy (a hardcore rock/screamo band from japan) at 120+ DB to stay awake.
December 24, 2006 10:29:07 AM

Yes it's understandable as in what you said makes sense and I certainly also believe you.

But I'd also like to know the underpinnings of why that is the way it is. Since you're tired, maybe someone else can point it out or maybe refer me to an article or something. Thanks by the way!
a b } Memory
a b K Overclocking
December 24, 2006 3:26:06 PM

Well, deadlydude wanted us to believe that memory rated for CAS5 overclocked better than memory rated at CAS4. He was speaking of ratings, not manual settings.
December 24, 2006 6:30:02 PM

Quote:
Well, deadlydude wanted us to believe that memory rated for CAS5 overclocked better than memory rated at CAS4. He was speaking of ratings, not manual settings.


I spoke poorly...I just wanted to say that LOOSENING the timings (manually) helps stability in an over-clocked system. Tighter rated timings are better performers. There is a good article here concerning how much performance increase there is:
http://www20.tomshardware.com/2006/03/31/tight_timings_...
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