Undervolting Skylake-U Imrpoves Performance During CPU+GPU Loads

Page 2 - Seeking answers? Join the AnandTech community: where nearly half-a-million members share solutions and discuss the latest tech.

Spektater

Junior Member
Sep 8, 2021
4
0
6
Hello everyone!

I know this is an old post, but I have that exact same processor (i5-6200U) paired with a 940m, and looking to undervolt, as the temps and fan noise get a bit annoying.

Thing is, XTU doesn't allow the option to lower the voltage offset (option appears grayed out). Maybe this is because my old processor requires an older version of XTU? If so, please let me know which version number of XTU I should download.

Any advice or input on this matter will be greatly appreciated!
 

Spektater

Junior Member
Sep 8, 2021
4
0
6
Probally because Intel removed the functionality because of Plundervolt.
Thank you for the quick reply! I'd never heard of Plundervolt, but did some quick googling, and it says it shouldn't affect general users who don't use specific SDKs.

Is there any way I can still undervolt? Maybe using ThrottleStop? Or has Intel completely removed the option through BIOS and there's nothing I can do?
 

rainy

Senior member
Jul 17, 2013
486
374
136
Is there any way I can still undervolt? Maybe using ThrottleStop? Or has Intel completely removed the option through BIOS and there's nothing I can do?
You should definitely check ThrottleStop which is a great tool, alternatively you could try also Quick CPU.
 
Last edited:

coercitiv

Diamond Member
Jan 24, 2014
5,160
8,269
136
Is there any way I can still undervolt? Maybe using ThrottleStop? Or has Intel completely removed the option through BIOS and there's nothing I can do?
Depends on your current BIOS version. I suggest installing Throttlestop, it will also tell you voltage is locked in BIOS. There's a dedicated section for Throttlestop on the Techpowerup forums, and the author of the software is active there (unclewebb). Browse the section and you'll see what the software can do for you, example bellow:
https://www.techpowerup.com/forums/threads/throttlestop-not-working-anymore.286384/

If your BIOS is already updated and locked, downgrading may be a risky move all things considered. On the other hand, you have more options other than undervolting, since your problem is mostly related to temps/noise and not performance itself. Simply limiting the speed of the CPU may help you get desired results. Last but not least, consider replacing the thermal paste on your CPU and GPU, on some some old laptops this can help quite a bit with fan noise, as the original paste dries up (and is usually applied in a rather thick layer too). Only consider this if you're comfortable opening up the unit.
 

Spektater

Junior Member
Sep 8, 2021
4
0
6
Depends on your current BIOS version. I suggest installing Throttlestop, it will also tell you voltage is locked in BIOS. There's a dedicated section for Throttlestop on the Techpowerup forums, and the author of the software is active there (unclewebb). Browse the section and you'll see what the software can do for you, example bellow:
https://www.techpowerup.com/forums/threads/throttlestop-not-working-anymore.286384/

If your BIOS is already updated and locked, downgrading may be a risky move all things considered. On the other hand, you have more options other than undervolting, since your problem is mostly related to temps/noise and not performance itself. Simply limiting the speed of the CPU may help you get desired results. Last but not least, consider replacing the thermal paste on your CPU and GPU, on some some old laptops this can help quite a bit with fan noise, as the original paste dries up (and is usually applied in a rather thick layer too). Only consider this if you're comfortable opening up the unit.
Thank you very much for such a detailed answer! I will definitely install Throttlestop and give it a try.

I feel stupid having manually updated the BIOS about a year ago, when I hadn't heard about undervolting. Now I would be hesitant to downgrade the BIOS considering the risks it involves. I hope there is some way to still undervolt with the "new" BIOS.

Limiting the speed of the CPU is something I would rather avoid. While I don't complain on performance (it is an old laptop, and I know I have to moderate my expectations), it definitely doesn't have any leeway for decreasing performance.

I THINK (based on use only, no real tests) I don't get thermal throttling, but I'll have to check on this.

I'm planning on repasting the CPU and GPU (which share one same copper heatpipe, probably a bad idea). I have "disassembled" the laptop before to slot in an SSD and do some cleaning, but I have never removed the cooling "block".

I'm afraid I might mess something up while repasting, and having an even worse performance than with the old factory paste. Is this possible, or am I just being paranoid?

Sorry for the wall of text. And thank you again so so much for all your help!
 

coercitiv

Diamond Member
Jan 24, 2014
5,160
8,269
136
Limiting the speed of the CPU is something I would rather avoid. While I don't complain on performance (it is an old laptop, and I know I have to moderate my expectations), it definitely doesn't have any leeway for decreasing performance.
There's many ways you can go about this, but you'll need to get more acquainted with Throttlestop. For example you can simply lower the max power allowed for longterm use, or just the one used for Turbo. Sometimes all the laptop cooling needs is just a few less watts and noise will become acceptable. (this also depends on your laptops cooling profile though)

You can also setup different performance profiles for when you need more performance or less noise. Throttlestop is a very complex software, since the developer worked on it for many years, keeping up with an increasingly complex power management system in modern CPUs.

As long as you're willing to invest some time into this, you'll learn to use the software and eventually will have a lot more control over how your CPU behaves.

I'm planning on repasting the CPU and GPU (which share one same copper heatpipe, probably a bad idea). I have "disassembled" the laptop before to slot in an SSD and do some cleaning, but I have never removed the cooling "block".

I'm afraid I might mess something up while repasting, and having an even worse performance than with the old factory paste. Is this possible, or am I just being paranoid?
Not much to worry, just use a good quality non-conductive thermal paste, if in doubt start your search with Arctic MX-4 (you want something not electrically conductive, good thermals, and stable for a long time); for laptop CPUs I prefer using a spatula to evenly spread a thin layer of paste on the die, since the cooler won't be able to apply much pressure to distribute the paste evenly. Try to add as little paste as possible while making sure the die surface is no longer visible.

Make sure you're grounded before you start, to avoid any static electricity issues. Work slowly, progressively loosen the screws. The manufacturer may have marked a recommended order for the screws, otherwise just loosen them all a bit progressively before removing them one by one. When tightening them do the same in reverse.

After changing the paste it may take a few thermal cycles before peak performance is achieved. Just use the laptop as you normally would.
 

Spektater

Junior Member
Sep 8, 2021
4
0
6
There's many ways you can go about this, but you'll need to get more acquainted with Throttlestop. For example you can simply lower the max power allowed for longterm use, or just the one used for Turbo. Sometimes all the laptop cooling needs is just a few less watts and noise will become acceptable. (this also depends on your laptops cooling profile though)
Maybe I should clarify is that I use the laptop for gaming often. I know this is a fool's thing to do, especially on an old laptop, but it's the only computer I have available to me. Reducing Turbo would probably kill my gaming performance, as it is already spread thin as it is (although the biggest bottleneck is GPU, which is only a 940m). From the quick research I've done, undervolting NVIDIA GPUs with MSI Afterburner's curves is only possible from Pascal onwards :(

Regarding the performance profiles, that could be interesting, as I could have a work profile with much less CPU power and quieter fans (although the noise/heat problem is obviously much more annoying while gaming, and barely a minor nuisance with standard work use).

I will definitely look into repasting then. My fear is I will have to repaste very often due to good quality thermal paste being expensive in my country, so I would probably end up using a low range one. But as long as I can go two or more years without repasting again, I'm happy.

Thank you for all the advice, will make sure to be grounded and disassemble carefully. Regarding peak performance, I'll be happy with anything that doesn't sound like a jet engine while gaming.

Currently I am using a tool called SpeedFan to try and have fans be less agressive, but I'm unsure as to safe temperatures. I have set a "warning" limit of 70°C for both cores of the CPU and for the GPU, so I guess fans go to the max whenever temps go above 70. While gaming, temps reach around 80, which I guess is getting close to dangerous temps for the longevity of the laptop.

Thank you again for everything!
 

LightningZ71

Golden Member
Mar 10, 2017
1,393
1,539
136
Have you actually monitored your CPU and GPU loads while gaming? From the sound of your configuration, you may be GPU limited in most of your games, so doing what you can to reduce the thermal load of your CPU can give more cooling headroom to the GPU. Take the time to understand where your limitations are first before you start messing with things.
 

ASK THE COMMUNITY