2000MHz DD3 Overclocking Help

[ConformalAnomaly]

First and foremost thank you to Clunk for his awesome Core i7 Overclocking Guide For Beginners. I have achieved a stable 4.0 GHz overclock of my Core i7 920 following his guide. I've used the following settings:

Memory: @ 1,524 MHz.
BCLK: 190
Load-Line Calibration: On
CPU Volt: 1.1275
QPI Volt: 1.3
DRAM Bus Volt: 1.65

I'm trying to utilize my Corsair DDR3 PC3-16000 (2000 OC) 8-8-8-24 to it's fullest. I tried to step up the memory ratio so it's at 1,905 MHz, but I am getting intermittent freezing (sometimes rebooting) when stress testing with P95. My system is stable with the above settings, but I can't seem to push the RAM anymore. I've tried upping the QPI Volt too with no luck. Ideas? Am I missing something? Are there other voltages that need some bumping when taking RAM up to this level?

Thanks in advance!

[kitfit1]

Welcome to the forum.

The best way for anyone to give you some help is to fill out your system specs first, so we all know what to advise on.

[ConformalAnomaly]

Thanks!

Here are my system specs:
CPU: Intel Core i7-920
Overclock: 3.990 GHz
Mobo: Asus Rampage II GENE
RAM: 3x2GB Corsair DDR3 PC3-16000 (2000 MHz OC) 8-8-8-24
PSU: Corsair HX750
Graphix: BFG GeForce 7950 GX2
HD: 2xWestern Digital Velociraptor 150GB
Cooling: Corsair H50
Case: Thermaltake Lanbox

[BlackDragon24]

Hello and welcome,

Only one way to achieve a 4ghz OC with 2000 memory on a 920 and thats by running 20 x 200 bclk with 2000 memory.

I would ensure that your cpu can run 20 x 200 comfortably with 1600 memory before attempting to approach 2000 memory, as 2000 memory is very tricky to get stable on some setups. This can be done by manually setting the multipler to 20, or by disabling the turbo function, and simply raising the bclk to 200. Sometimes this requires a slightly higher voltage than the 21 x 191.

[ConformalAnomaly]

Thanks for your input. How come I cannot increase the CPU-DRAM clock ratio from 1:8 to 1:10 at 21x190? Why does it need to be at 20x200?

[BlackDragon24]

Well it doesn't need to be at 200 unless you want to run your memory at 2000 mhz. Your memory will run on a multiplier of your bclk so if you are running 190 bclk the memory will run at 1900mhz.

My suggestion was to make sure that your processor was stable using 20 x 200 first, along with 1600 memory. Once you have established a safe voltage for 20 x 200 (sometimes it requires slightly more voltage than 21 x 191 because of the higher bclk) then you can raise the memory ratio and bam you are at 2000 mhz. Sounds easy enough but usually it involves some tweaking.

So what are you using to determine stability?

[ConformalAnomaly]

Well I am stable now at 21x190 after a few hours of Prime95. What I was asking is why can I not just raise the memory ratio now so I am at 1,900 MHz? I stabilized 21x200 earlier today, but the temps are higher than I'd like under simulated load (Prime95 again).

[kitfit1]

Well I am stable now at 21x190 after a few hours of Prime95. What I was asking is why can I not just raise the memory ratio now so I am at 1,900 MHz? I stabilized 21x200 earlier today, but the temps are higher than I'd like under simulated load (Prime95 again).

The reason for not changing the mem ratio at the moment, is to make absolutely certain that your cpu is 100% stable first. It's much easier to get stable with your mem at 1600, plus, if the clock is not stable you know that the problem is unlikely to be your mem and more likely to be your cpu.

As BD has said, some mobo/cpu/mem combinations simply do not like running with the mem at 2000, even if the mem is specked as 2000. Once you have run 20 rounds of Linx and 8+hours of Prime Blend, then it's time to move your clock onwards.

[BlackDragon24]

The reason for not changing the mem ratio at the moment, is to make absolutely certain that your cpu is 100% stable first. It's much easier to get stable with your mem at 1600, plus, if the clock is not stable you know that the problem is unlikely to be your mem and more likely to be your cpu.

As BD has said, some mobo/cpu/mem combinations simply do not like running with the mem at 2000, even if the mem is specked as 2000. Once you have run 20 rounds of Linx and 8+hours of Prime Blend, then it's time to move your clock onwards.

Thanks kitfit1....sometimes I just forget that this stuff can be really confusing

@ the OP: Just like kitfit1 said, we are trying to make sure your cpu is stable before we raise the memory speed because once you cross the 1600 memory speed barrier on the i7 platform, things can get tricky quickly.

If you are interested in getting your memory at spec, i.e. 2000 with 8-8-8-24, there is only two ways you can do that logistically. One would be to run at 200 bclk and set your memory ratio to 1:10 (10 x 200 = 2000). The other would be to run at a lower bclk of 166 and set the memory to a 1:12 ratio (166 x 12= 2000ish). Since running at 166 bclk limits your cpu overclock on a 920 (most you could get would be 21 x 166) then 200 bclk is the choice of champions . So, if you are interested in getting your memory at spec of 2000 8-8-8-24, then you will have to demonstrate that your processor is stable at 200 bclk. It doesn't matter if its 19 x 200 or 20 x 200 or 21 x 200. Since you are stable at 21 x 191 which is essentially 4ghx I suggested dropping the multiplier to 20 and raising the bclk to 200, which will give you the same essential speed but will allow you to bump the memory to 2000 once you have gotten it stable.

If you don't care about running the memory at spec of 2000 8-8-8-24 than you can by all means just raise the memory speed at your 21 x 190 and have 1900mhz memory. I would guess that with that memory you will probably need in the range of 1.3-1.35 QPI voltage, but each cpu is very different.

[ConformalAnomaly]

Maybe I should rephrase, because I think you guys are missing what I am asking for (although I appreciate all of your help). I KNOW how to set the memory to 2000 MHz. I know how the math works and the different combinations of the memory ratio/BCLK to CPU ratio that it would take to reach the number I want "on paper". When I try to actually do it I'm getting freezing though, and I don't know what voltages/settings should be adjusted to assist in stabilizing the speed step up. Do the IOH or ICH voltages help? More QPI volts?

I know the CPU overclock is stable at 21x190. I ran Prime95 (always do blend unless I'm just testing for max temp) for around 12 hours last night. Woke up, no problems.

So what other settings would aid in supporting the memory being stabilized at the next step up at 1:10 (1900 MHz in my case)?

Thanks for your help thus far.