Author Topic: Undervolt your CPU today!  (Read 128 times)

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Offline Mave

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Undervolt your CPU today!
« on: September 14, 2017, 03:21 »
After complaining about high temperatures on my new laptop while gaming on the notebookreview forums, I found out about undervolting thanks to user hmscott.
Since then my CPU temps have dropped under heavy load for +30mins from 98 degrees Celsius to 88 degrees Celsius.
Time to share my new knowledge.



Undervolting your CPU

Advantages

  • Bettery battery life (minimal difference, but still)
  • Cooler temperatures (typically 10 degrees Celsius difference)
  • Less fan noise (logical effect of cooler temperatures)

Downsides

  • None, the performance does not suffer one bit, the only thing that affects performance is clock speed, not voltage

Why it's possible

Intel builds a LOT of CPU's.. But not every CPU is the same. Actually most CPU's can run with a lower voltage, but Intel can not fine-tune every single CPU out there. And if they lowered the voltage for all CPU's, some customers would get CPU's that don't have enough voltage!
This is why they released a tool that allows you to do so yourself!

Tutorial: how to undervolt your CPU

Before you start this tutorial, it's useful to know how hot your CPU runs under heavy load.
Play your favorite performance-heavy game and leave HWmonitor open for the entire duration. Afterwards note your maximum CPU temperatures.

NOTE: Your system WILL give your a Blue Screen Of Death or freeze when the voltage is too low. But:
Don't panic! Every system crash, the changes will be undone automatically. This is built in in the XTU utility.
This is why I included the second step.



  • Download and install Intel Extreme Tuning Utility or XTU from https://downloadcenter.intel.com/download/24075/Intel-Extreme-Tuning-Utility-Intel-XTU-
  • Close important programs where you don't want to lose data (open office files etc)
  • Open XTU, navigate to the Core tab under "Advanced Tuning"
  • Look for the "Core Voltage Offset" and turn it down by -0.100V, then click Apply in the right column.
  • Your system didn't crash (BSOD) or freeze? Continue to the next step
  • Lower your offset by one clicks (0.005V), then click Apply in the right column.
  • Your system didn't crash (BSOD) or freeze? Repeat the previous step
  • Your system did crash (BSOD) or freeze? Go up  +0.01V. You are now at a stable idle voltage offset.
  • Test your system first doing casual things, like browsing web, music,.. whatever.
  • Time to stress test. Navigate to "Stress Test" in XTU and stress test your system for 5 minutes.
  • Your system still didn't crash (BSOD) or freeze? Great! Now try running that same game for the same period and monitor your temperatures again with HWmonitor
  • If your system survived this last test, then great! You got yourself a cooler CPU now! Save the Offset and it will be applied automatically when you boot. (It will however get reset on every system crash as protection)
  • If your system did crash, try going back up a few voltages and try again

For me personally the sweet spot was -0.135V, -0.145 and -0.155 gave me BSOD or system freezes.
Testing -0.140 at the moment to see if that's an option as well.

« Last Edit: September 14, 2017, 03:23 by Mave »

Offline Stybar

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Re: Undervolt your CPU today!
« Reply #1 on: September 15, 2017, 03:14 »
Great tutorial, Mave. However, I have a watercooled system, so... I'm good, thanks :)

Offline Mave

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Re: Undervolt your CPU today!
« Reply #2 on: September 15, 2017, 05:49 »
Great tutorial, Mave. However, I have a watercooled system, so... I'm good, thanks :)
Nice, what temps do you maximum get with a watercooled system?

Offline Stybar

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Re: Undervolt your CPU today!
« Reply #3 on: September 16, 2017, 01:46 »
Great tutorial, Mave. However, I have a watercooled system, so... I'm good, thanks :)
Nice, what temps do you maximum get with a watercooled system?
Maximum I hit around 55 Celsius, while playing Forza Horizon 3. Just browsing, I stay about 32-34 Celsius.

Offline Mave

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Re: Undervolt your CPU today!
« Reply #4 on: September 16, 2017, 02:03 »
Great tutorial, Mave. However, I have a watercooled system, so... I'm good, thanks :)
Nice, what temps do you maximum get with a watercooled system?
Maximum I hit around 55 Celsius, while playing Forza Horizon 3. Just browsing, I stay about 32-34 Celsius.
That's pretty damn neat.
Mind sharing a picture? I've never seen a watercooled system in my life lol.

Offline Stybar

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Re: Undervolt your CPU today!
« Reply #5 on: November 05, 2017, 09:40 »


It's not that special, since it's just black anyway.

Also, late response, because it's a fucking hassle to take a pic of my guts. The side of my case that opens is towards my wall.

Offline Mave

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Re: Undervolt your CPU today!
« Reply #6 on: November 05, 2017, 06:40 »
You're right, doesn't look that special. I was expecting something more cool since I never saw a watercooled pc before, but I just googled around a bit and they all kinda look like this. (some added neon for god-knows-what-reason.

Offline Stybar

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Re: Undervolt your CPU today!
« Reply #7 on: November 05, 2017, 08:09 »
Yeah, some people do that. I guess I can understand why if you have a massive window in your case, but since I don't... TBH, I explicitly took watercooling just so I didn't have to worry about replacements for the next 2-3 years, and since it's going smoothly for over 20 months now, I'd say I choose well. The only upgrade I'd get now is a 1070 GTX or something, but so far my 970 is performing without problems.