# [SOLVED] Core i5-750 3.2 GHz Overclock Help



## PRSF

Hi guys

I have been trying to get 3.2 GHz on my new i5-750 stable lately. I have tried various settings but it always ends up having Prime produce an error, sometimes after 30min, sometimes after 1.5hrs.

The most stable setting so far has been 160 BLCK, 20x multi, 1.235v Vcore, 1.15v IMC, 1.65v DRAM with 8-8-8-24 which is the rating for my Dominator RAM. Leaving all other settings on auto for RAM and everything else. It runs my RAM at 1N by default, not sure if 2N would be better or even using 9-9-9-24 isntead of what they are suppose to run at.

With those settings Memtest86+ did not produce any error after 2 passes but Prime is still not being nice. I had played for several hours of Starcraft 2 without issues, no BSODs or anything....

Could anyone point me in the right direction or what I could try, perhaps even their settings for 3.2 GHz on the i5, my board is an ASUS P7P55D-E PRO



Also




I have been wanting a very mild overclock with turbo boost enabled, I have read others saying they can have their multi on a fixed setting, such a 20x, and have turbo boost enabled, however on my board unelss I have the multi on auto turbo boost is not available in the BIOS, speedstep and c-state are but not turbo boost.

I have been trying 140 BLCK for 2.8 GHz with turbo boost, leaved the vcore on auto which didn't do above 1.27v on load but Prime failed. I would ideally like 2.9 GHz with turbo boost meaning 145 BLCK, but I am unsure what settings for the vcore I should put, as I would assume you would want it to still drop down under 1v when the multi is a 9x with the system idle, should I just use offset and raise the volts a little?

Thanks for any advice


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## greenbrucelee

*Re: Core i5-750 3.2 GHz Overclock Help*

do not change the multiplier, upping the multiplier is the wrong way to overclock.

you should be upping the FSB you should easily be able to get to 3.5.

what cpu cooler do you have?

switch turbo booste off and see if the system becomes stable. Also have you disabled C1E and intel speedstep?


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## PRSF

*Re: Core i5-750 3.2 GHz Overclock Help*

Hi, thanks for the reply

My CPU cooler is a Zalman CNP9900 NT, my temps while Prime testing never go above 50C

I have SpeedStep, Turbo and C-State disabled.

I am not overclocking by up'ing the multi, I set my BLCK at 160 raised from 133, weather I leave the multiplyer on auto or set it to 20x the frequency is still the same, 3.2 GHz, are you saying I should just leave the multiplyer on auto and only set the BLCK to 160?

I don't really see how that makes any difference considering the multiplyer is set to 20x when on auto at that base clock. The only difference is if I leave the multi on auto I have the ability to enabled Turbo Boost, while when it is set to a specific multiplyer turbo boost vanishes as an option in my BIOS, though Speedstep and C-state are still available, I still disabled all power saving features for the CPU

Do you really think just leaving the multi on auto will make that much a difference? Like I said with those voltage settings it's pretty darn stable, but I still fail Prime.....
If I have my voltages on auto I can't even boot into windows before it blue screens....


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## greenbrucelee

*Re: Core i5-750 3.2 GHz Overclock Help*

you can manually set the multi to 20x but you don't have to increase or decrease it. This is how you overclock.

you have to switch the turbo boost off because it will affect your overclock
set the ai tuner to manual
set the BLCK to 160
set the voltage to the next available one (will probably take until 1.67 before a stable boot) but only increase it in small increments.
set the ram voltage to what the manufacturer states
enter ram timmings (optional)
save & reboot

if you get a succesful boot go back and increase the BCLK to the next available one and repeat the process

next stress test for one hour with OCCT whilst monitoring the temps.

when you get to an overclock your happy with then stress test for 6 hours + with prime 95


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## PRSF

*Re: Core i5-750 3.2 GHz Overclock Help*

Hey, thanks for the reply again

I am aware of all that and am not a complete noob at overclocking, though this is my first 1156/1366 overclock.

I have achieved a stable boot into Windows, and have ran Prime for a short amount of time with no errors, but, when I finally run an extended Prime test it produces an error after approx. 1.5-2hrs, and regardless of the voltage increase I do not seem to be able to achieve a fully stable system.


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## greenbrucelee

*Re: Core i5-750 3.2 GHz Overclock Help*

it may not be the cpu that is unstable it may be to do with the ram.

did you run the full cpu stress test? do this an see if you get errors, if you do not then it's most likely the ram

make sure the ram speed has not gone above its rated speed i.e not above 1600 if it has you need to drop the dram speed down to below 1600


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## PRSF

*Re: Core i5-750 3.2 GHz Overclock Help*

Thanks man that's what I was looking for.

I had read some reports about the Dominator RAM that I have, saying they were unable to get it stable at the 8-8-8-24 timming its rated for. Others saying it also wasn't able to be stable at 1600 MHz either.

I was kinda thinking that maybe I needed to try 9-9-9-24, which I now have it set at and am currently testing these settings:
160 BLCK
20x multi
1.2375 vcore
1.15 vtt
1.65 DRAM
1600 MHz DRAM
9-9-9-24

Hour of Prime has resulted in no errors, lets see how a few more hours do......fingers crossed.

If it does produce no errors with 9-9-9-24 I'm gonna make a post on the Corsair support forums and see what they think about it.

I replaced my XMS RAM with the Dominator RAM cause I had really good success with it in my 775 rig, also the tighter timmings were a plus, so I'm hoping this RAM isn't bad as well, though I have passed several passes of Memtest86+ with stock default settings and my current settings, even with 8-8-8-24, but I know it's not as stressful on the system as Prime is.


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## greenbrucelee

*Re: Core i5-750 3.2 GHz Overclock Help*

usually its not the timing that are the problem but the actual speed in your case 1600. When you increase the FSB anything connected to it has its speed increased this include the ram and the graphics card aswell as the cpu. The aim is to increase the FSB without going to far below or anywhere above the FSB speed of the ram and manually setting the graphics card pci-e to 100

take my overclocked system which is a 3GHz e8400 running at 4GHz my ram is 1066MHz but I can only get it to 1064 or 1070. 1070 makes me unstable, 1064 does not.


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## PRSF

*Re: Core i5-750 3.2 GHz Overclock Help*

Yea man when I set my BLCK to 160 and set my RAM to 1600 MHz, it says it is actually 1604 MHz, so perhaps I should tone it down and set it to something like 1450 MHz or whatever the setting is below 1600?


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## greenbrucelee

*Re: Core i5-750 3.2 GHz Overclock Help*

yep you just need to get it below 1600 and you will be okay.


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## PRSF

*Re: Core i5-750 3.2 GHz Overclock Help*

Hey guys

Well I tried my overclock using 159 BLCK and set my RAM timing to 1580 MHz I think the setting offered was, something around that, just under 1600 MHz, Prime still found an error, so it seems that setting is not stable either.....

Should I even bother trying 160 BLCK and 1280 MHz? That is the only other option besides 1600 MHz at that setting, which I really don't think would be a good idea considering it's not even 1333 MHz



On another note, I was playing with a 1366 socket board the other day, guy had an i7-960! It had the ability to set the DRAM frequency to 1333 or 1600 without even changing the BLCK, why are 1156 sockets not able to do this.....or was it due to his CPU installed?


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## greenbrucelee

*Re: Core i5-750 3.2 GHz Overclock Help*

overclocking is all about experiementing and making sure all your hardware works well together. JUst because someone in an overclocking guide did really well with your cpu doesn't mean you will,

do not use the 2N setting leave it on normal.

question do you have 4 1GB ram sticks or 2x2GB?

1156 are better for overclocking I think your going wrong somewhere. Please post everything you have done in the BIOS


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## PRSF

*Re: Core i5-750 3.2 GHz Overclock Help*

Hey man, thanks again for the reply

I am aware that every CPU is different and just cause someone got 4 GHz doesn't mean I will, but 3.2 GHz I would think it should be able to do easy.

I have my RAM set at 1N, or rather, that's what it sets itself to on auto, have already tried 1N manually.

I have 2 x 2 GB sticks of RAM, and they are installed in the proper blue slots.

BIOS settings I have changed:
AI Overlock: Manual
-Q-FAN for CPU FAN enabled (tho I monitor temps carefully and never get above 50C under load, usually 28C idle, 48C under load approx.)
-BLCK: 160
-CPU Multiplyer: 20x
-DRAM Frequency: 1600 MHz
-DRAM timing: 8-8-8-24
-DRAM Voltage: 1.65V
-CPU Voltage: 1.235 (have tried a little lower and higher)
-IMC Voltage: 1.15 (have only tried a little higher once, perhaps this is what needs to be raised for potential stability in my case?)

That's all I've changed, besides boot device priority and Express Gate countdown.


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## greenbrucelee

*Re: Core i5-750 3.2 GHz Overclock Help*

try this allthoug it might be a pain.

reset back to default with everything.

BLCK 155 (or the closest you can get)
Leave the multiplier alone
Leave the DRAM frequency alone unless it is above 1600 it must be at or below 1600
Leave cpu voltage alone unless it wont boot the max voltage is 1.45 for this cpu

RAM 8-8-8-24
Dram voltage set to manufacturers stated level
Leave the IMC alone this is the intergrated memory controller very rarely does it need changed.
disable C1E and Intel speedstep and knock any turbo boost options off.

see what happens and let me know.


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## PRSF

*Re: Core i5-750 3.2 GHz Overclock Help*

Alright so update

I did what you said and it booted, however my vcore was running at 1.36v, which I really wouldn't want to run my system at, that is really high voltage!

I really don't want to go over 1.25v with overclocking, as many have said they got good results with that voltage, and is basically safely within "intel spec". So I set it to 155 BLCK and 1.25v, set the RAM accordingly and left the IMC on auto, it booted and seemed to be running good, got through about 3hrs of Prime.......but then it found an error....damn!

I also tried to play with the IMC a bit, and whatever I set it to, 1.15v, 1.2v, which I had done before, it gave me BSODs this time.

I tried 160 BLCK with 1.25v and unless I left the IMC on auto like you suggested, it wouldn't even load into Windows without a BSOD, which is really weird because I had it booting and working pretty good before with those settings, why it doesn't work now I really have no idea.

From everything I'v read on OCF (overclockforum) 1.35v etc is a real high voltage, most people are running at 4 GHz with that voltage, would you feel comfertable running that high voltage for just a 3.1-3.2 GHz OC?

I do not know why I can't get it stable with 1.25v and only 155 BLCK, which has my RAM running at 1550 MHz, all other RAM settings are to Corsair specs

argh! lol


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## greenbrucelee

*Re: Core i5-750 3.2 GHz Overclock Help*

it all depends on how good the hardware works together. you might have to keep it at 1.35 that could be your only option. It is quite high but it is within spec.


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## PRSF

*Re: Core i5-750 3.2 GHz Overclock Help*

well I think I got it!

4hrs of Prime and everything is fine

155 BLCK settings currently

What I changed was my RAM timing to 2N from 1N, I enabled XMP and noticed it set my RAM to 2N instead of 1N, however auto leaves it on 1N and I had thought my Dominator RAM was 1N

So really, is there any way to have it run stable at 1N if I seem to only be able to get it stable at 2N, and what is the real disadvantage to 2N, am I going to notice any significant decrease in performance?

Thanks


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## greenbrucelee

*Re: Core i5-750 3.2 GHz Overclock Help*

i never use those N settings for my Asus boards I find they screw things up. PLus 4 hours of prime isn't enough to say you have a stable system. It should be 6 hours minimum.


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## PRSF

*Re: Core i5-750 3.2 GHz Overclock Help*

12hrs Prime stable at 160 BLCK, 3.2 GHz, seems stable

from what I'v read also it seems to only be a difference of 3.3% in performance between the two command rates.......is that about right


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## greenbrucelee

*Re: Core i5-750 3.2 GHz Overclock Help*

Yep its only about 3% maybe a little over, but looks like your stable.

Well done.


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## PRSF

*Re: Core i5-750 3.2 GHz Overclock Help*

Thanks for all your help man, seriously, it was really appreciated.

I felt, as you did, it was something to do with the RAM, although I was finally able to reach 1600 MHz stable, I'm very pleased.

Again the only reason I tried 2N was because XMP automatically set my RAM to 8-8-8-24 2N, so if that's what Intel/Corsair think it should be set to, I guess that's what it should be set to.

I'm currently playing around with turbo boost overclock, right now I'm testing 145 BLCK with turbo boost, so 2.9GHz w/Turbo to 3.55 GHz approx. seems to be running good!

Since I don't use my system constantly for gaming etc, I would like my system to idle with lower voltage etc when I'm just surfing the net, I have my 3.2 GHz profile saved in my BIOS however.
I might try as high as 150 BLCK/ 3.0 GHz w/Turbo, when my multi maxes, my vcore seems to go as high as 1.28v, not too bad since it won't be doing that constanly.

Again, thanks a bunch man


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## greenbrucelee

if you ckeep c1e and intel speedstep on then the speed will lower when you are surfing the web etc so it wont use all the voltage


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## PRSF

That's the plan man lol

Right now I have my BLCK set at 145, CPU running at 2.9 GHz when it hits 20x multi, with turbo boost at its max it hits about 3.55 GHz as I stated above.

C1E, Speedstep (which needs to be enabled for TurboBoost to be available) and TurboBoost.

It's running great, totally stable, wicked fast, I have my 3.2 GHz saved in BIOS OC profile for when I want to run all 4 cores at that speed, but really I don't have any program that needs anything more than what it currently has, plus then I'm not running my vcore at 1.24v all the time, which is great, way less demand on the board/chip


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