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Need help overclocking Phenom II X4 940 BE

Last response: in Overclocking
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November 16, 2010 11:17:40 PM

Specs:
CPU: Phenom II X4 940 Black Edition (3.0ghz stock)
FAN: ZALMAN CNPS 9700 NT
MOBO: MSI 785GT-E63
RAM: 4GB OCZ GOLD XTC DDR2 800 (4x1GB Dual Channel) (ocz2g8002gk)
PSU: Corsair HX 650W
GPU: XFX Radeon 5770
CASE: Antec Sonata III
OS: Windows 7 32-bit

I read this article and turned off everything it suggested:
http://www.tomshardware.com/reviews/phenom-overclock-at...

I'm trying to achieve 3.5ghz overclock just by raising the multiplier to 17.5

I have Vcore set to 1.375v

I manually set my ram timings to 5-5-5-12 @ 2.1v (rated timings and voltage)

All seems good, but whenever I run Prime95 blend test I get BSOD (Blue Screen) almost instantly.

I can run Prime95 small FFT with no problems.

I tried memtest86+ and no errors.

With everything at stock, no overclocking and everything set to auto, I can run Prime95 blend test for hours.

What am I doing wrong? I've been researching for days and I can't figure out what's causing the blue screen. I have a feeling it might be my ram, but I'm not sure. If you can give me any advice or tips I'd be extremely thankful.

Best solution

a b K Overclocking
November 17, 2010 5:59:08 AM

I would try pushing the cpu voltage up further, the Phenom II 940s don't overclock as well as the newer Phenom II processor and required more voltage. I've personally got one running 3.6Ghz with 1.45V.
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a c 295 K Overclocking
November 17, 2010 2:01:01 PM

BSoD means more CPU voltage.
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November 17, 2010 2:41:13 PM

loneninja said:
I would try pushing the cpu voltage up further, the Phenom II 940s don't overclock as well as the newer Phenom II processor and required more voltage. I've personally got one running 3.6Ghz with 1.45V.


Thanks, I will try upping the voltage or maybe I will try lowering my multiplier. I feel like my cpu is running hot as it is and increasing my voltage will only make it hotter.
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November 17, 2010 2:45:31 PM

saint19 said:
BSoD means more CPU voltage.


I was able to pass Prime95 small FFT test, and that's why I thought my cpu overclock was okay. It's the blend test that's causing the blue screen, and from what I read that also stresses the ram. BSOD can't be caused by my ram?
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a c 295 K Overclocking
November 17, 2010 3:28:05 PM

Are you changing something in your RAM? I don't think so, the only logical option is the CPU.
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November 17, 2010 4:57:32 PM

saint19 said:
Are you changing something in your RAM? I don't think so, the only logical option is the CPU.


Looks like upping the voltage worked! I changed the core voltage to 1.40v and left the multiplier at 17.5.

I was able to successfully run prime95 blend test without errors or blue screens.

But my cpu temps got as high as 64C. Is this bad? Should I just settle for a lower clock speed and lower the voltage as well? Thanks so much for your help!
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November 17, 2010 5:40:17 PM

Also, should I enable AMD Cool n' Quiet back now that my overclock is stable? Or do you usually leave it off permanently whenever your cpu is overclocked?
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a c 295 K Overclocking
November 17, 2010 6:02:19 PM

You can turn on Cool'n'Quite again.

I'd not go above 60ÂșC, so, lower the clock speed and voltage to keep the temps in a safe range.
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November 20, 2010 3:34:16 AM

Okay I thought I successfully overclocked my cpu but I can only run Prime95 blend test for about an hour and then my computer unexpectedly reboots.

My temps were okay around 60C

Multiplier at 17.5

CPU Voltage 1.40v

I was aiming for at least an hour for stability but my computer restarted after 50 minutes.

Any suggestions?
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a b K Overclocking
November 20, 2010 7:12:58 AM

Have you manually set your ram voltage and timings or is it on auto?
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November 20, 2010 7:43:24 AM

loneninja said:
Have you manually set your ram voltage and timings or is it on auto?


I manually keyed in ram voltage and timings.
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November 20, 2010 8:00:07 AM

I decided to give up on 3.5ghz because if I raise the vcore any higher than 1.402v (next available voltage in BIOS is 1.412v) it's going to get too hot.

So I lowered my multiplier to 17 to give me a cpu clock speed of 3.4ghz. I tried running @ 1.352v but got a blue screen after 8 minutes of Prime95.

Upped voltage to 1.363v. Lasted longer but computer still rebooted.

Should I keep increasing the voltage by .01v until it becomes Prime95 stable?

For some reason it seems like my cpu is more voltage hungry than others...

Most articles and others' experience seem to be able to run 3.4ghz at stock voltage which is 1.35v.

Is it possible my RAM timings are too tight? What should I do? Keep raising the vcore? Buy new ram?

Thanks for everyone's help so far! I'm determined to get this overclock down!
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November 20, 2010 12:17:11 PM

Ok, let's start over and be safe...

First, set everything to auto (even your ram). Note that your RAM increases may cause the cpu to crash and you "think" its the cpu.
Second, ONLY change the mutliplier and try that. (Note: I was able to achieve 19.5x multi or 3.9Ghz without any voltage increases.)
Third, find how high the multi can go (in half increments) until you witness the blue screen of death.
Fourth, move the multi up a half-point above where it was stable at stock voltage and then increase the voltage only one or two clicks above stock. Run Prime95 AND core temp and watch the max temp during testing.
Fifth, remember that at some point you will be using too much voltage and no matter what you will crash.
Finally, go slowly. Don't rush voltages up to high.

(P.S. Saint19 helped me and now my 3.2Ghz stock cpu is running 4.1Ghz, so listen to him.)
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November 20, 2010 12:18:44 PM

Oh, turn off Cool and Quiet and CE1 before you begin.
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November 20, 2010 1:44:09 PM

ahthurungnone said:
Ok, let's start over and be safe...

First, set everything to auto (even your ram). Note that your RAM increases may cause the cpu to crash and you "think" its the cpu.
Second, ONLY change the mutliplier and try that. (Note: I was able to achieve 19.5x multi or 3.9Ghz without any voltage increases.)
Third, find how high the multi can go (in half increments) until you witness the blue screen of death.
Fourth, move the multi up a half-point above where it was stable at stock voltage and then increase the voltage only one or two clicks above stock. Run Prime95 AND core temp and watch the max temp during testing.
Fifth, remember that at some point you will be using too much voltage and no matter what you will crash.
Finally, go slowly. Don't rush voltages up to high.

(P.S. Saint19 helped me and now my 3.2Ghz stock cpu is running 4.1Ghz, so listen to him.)


If my last attempt didn't work I would have definitely tried all that. But I finally got it Prime95 stable for 2 hours. I just stopped the test on my own terms for the first time. :) 

It was just a matter of finding the correct CPU multiplier and Vcore sweet spot.

Lowered the multiplier to 17.
Set Vcore @ 1.375v

Max temp 58c

Wish I listened to Saint19 sooner and just lowered everything instead of being stubborn trying to get 3.5ghz. It has been a great learning experience.

Thank you everyone for your help!
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a c 295 K Overclocking
November 21, 2010 2:07:24 AM

Don't try the other users settings, those will never work for you, even if the components are the same.
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November 22, 2010 1:38:41 PM

Best answer selected by tacocat.
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!