1:1 vs 4:5 performance comparison?

HeavyB

Senior member
Oct 28, 2000
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I recently set-up a rig with P5B-Deluxe/E6400/Crucial Ballistix PC2-8000 and immediately overclocked to 3.2 with-out a hiccup. I'm not likely to run the CPU much faster than this, but am curious which CPU:RAM ratio should give the best performance, a 1:1 where the RAM and CPU are both running at 400 (mem 400X2) or a 4:5 ratio where the memory is running at 500X2 and the CPU at 400? I run 5-5-5-15 timings with the memory when over 1000Mhz, but should be able to tighten the timings if I go to 1:1 and run it at 800Mhz? TIA.

Cheers,
HeavyB
 

Duvie

Elite Member
Feb 5, 2001
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Uses vary so you will have to test it out...The added bandwidth is likely very useful in gaming apps....Likely you can get cas 4 at 800, but I dont think cas 4 to cas 5 with the Intel chips will be much of a hit considering you would have raised the speed of the ram and thus bandwidth.
 

The-Noid

Diamond Member
Nov 16, 2005
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4:5 offers much better performance on 965p. On 975x you are better off using 1:1.
 

cmdrdredd

Lifer
Dec 12, 2001
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set 2.3v on the memory and run 4-4-4-8 at DDR2-1000 (4:5) and it should be stable. Give it a shot. My Crucial 10tyh Anniversary is rated at DDR2-667 and I can run 5-4-4-8 at 1000Mhz.
 

n7

Elite Member
Jan 4, 2004
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4:5 = better.

Even if it's DDR2-800 4-4-4 vs. DDR2-1000 5-5-5, the latter is better.

But as cmdrdredd mentioned, you may very well be able to do 1000 4-4-4, which is better yet :D
 

eagle101

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May 29, 2004
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Originally posted by: n7
4:5 = better.

Even if it's DDR2-800 4-4-4 vs. DDR2-1000 5-5-5, the latter is better.

But as cmdrdredd mentioned, you may very well be able to do 1000 4-4-4, which is better yet :D

lifer look at my system what will be good settings for me ratio/ram settings etc..for oc. thanks
 

n7

Elite Member
Jan 4, 2004
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Well, that's a little hard to say since i don't know what your CPU/RAM maxes out at.

I don't know the P5W DH bios too well since it's not the same as my P5B-D's, but i'd say as usual, find your CPU max first, & then worry about RAM afterwards.

Because you have an X6800, you're multi unlocked, which allows you a huge amount of flexibility for overclocking.

I would likely try something like 9x400 (assuming you can get 3600 MHz) w/ 4:5 divider which gives you DDR2-1000 4-4-4 for your RAM.

I have heard 1:1 is very good on the 975X chipset though, so you may want to bench that against other configs to see how it does.

Your RAM should do DDR2-800 3-3-3 as well if you run at lower speeds 1:1

 

The-Noid

Diamond Member
Nov 16, 2005
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You will get best results on your system if you do 9x400 1:1 3-3-3-8 @ 2.4v.
 

n7

Elite Member
Jan 4, 2004
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Why do you guys insist on 1:1 being better when it's been shown it's not?

I don't give a flying eff about SuperPI.

Yoxxy, on your system, run 9x400 1:1 3-3-3 2T (since only users w/ 680i have 1T)

& then

9x400 4:5 4-4-4 2T

Now run 3DMark01 with that.

I bet you already know what is going to win.
Then bench a game or two. Again, tell me which one wins.

Unless you run synthetic benches for a living, bandwidth 4:5 > timings 1:1, & this isn't some new revelation either.

This is especially true with the P965 chipset, which people have noticed 1:1 is in no way better than higher ratios.

Sometime when i have more time i'll do some benching to show this, but really, there's a bunch at XS that already show this.
 

The-Noid

Diamond Member
Nov 16, 2005
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He is on 975x. 975x != 965. 1:1 has much, much higher bandwidth on 1:1 then on 4:5. There is just not two ways about it. There has not been one post that has differed on the fact that 1:1 is the fastest ratio for 975. 4:5 is much faster on P5b, but it is a different chipset from the ground up.
 

The-Noid

Diamond Member
Nov 16, 2005
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Its too close to call. Cas 3 actually works on 680i. So believe it it not its 6 of one half dozen of the other.
 

zizo

Member
May 9, 2005
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Originally posted by: Yoxxy
You will get best results on your system if you do 9x400 1:1 3-3-3-8 @ 2.4v.


I run 4:5 with 5-4-4-12 timings, which is even better than 1:1 3-3-3-8.
 

The-Noid

Diamond Member
Nov 16, 2005
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Cas 3 doesn't work on P5B. This is not an issue on other boards. 3-3-3-4 gets worse performance in * apps then 4-4-4-4, and much worse then 4-4-3-4.
 

zizo

Member
May 9, 2005
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Originally posted by: Yoxxy
Cas 3 doesn't work on P5B. This is not an issue on other boards. 3-3-3-4 gets worse performance in * apps then 4-4-4-4, and much worse then 4-4-3-4.

Exactly and we're not talking about other boards. OP has P5B Deluxe. ;)

 

lopri

Elite Member
Jul 27, 2002
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Well.. I'd say it's impossible to do a 'true' comparison unless we're given a full control over the chipset/memory parameters. The bottom line is, motherboard manufacturers play tricks with straps/latencies for one reason (performance) or another (compatibility), and without that knowledge we really don't know what is going on underneath. (It was one of the main reasons I didn't, and to some extent still don't, like P965 chipset) As Yoxxy precisely pointed out, playing with subtimings can make one divider win over the other, or vice versa.

Said that, in current BIOS many motherboards employ, higher memory frequencies seem to give better performance than tighter timings. Especially when sub-timings are left auto, the benefit of higher frequencies are even more pronounced. (Except some stupid cases like 1300MHz/5-6-6 on 680i) In the end, we all know the timings/frequencies are relative to bandwidth, and different chipsets will handle things differently, not to mention different BIOS. The definite way to determine the impact on performance is testing your own, under the desired CPU/FSB frequencies. I find the 680i chipset somewhat more responsive to memory configuration than 975X/P965, but even then, the difference is so small that it really doesn't matter unless your family's living standard is dependent on your benchmark numbers.

P.S. Why do you need 2.40V for 800MHz/3-3-3? :shock;
 

cmdrdredd

Lifer
Dec 12, 2001
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Originally posted by: Yoxxy
Its too close to call. Cas 3 actually works on 680i. So believe it it not its 6 of one half dozen of the other.

I can run DDR2-800 3-3-3-4 on my P5B-D