How to cool down CPU while encoding with GPU

[Arctic]

Hi folks, need your help please.

• I set Handbrake to NVEnc 264 + Very Fast 480p to encode a 4Gb mp4 file.
• Windows 11 is set for Handbrake to use NVidia GPU.
• CPU is cooled with 360mm Arctic Liquid Freezer.
• Task Manager shows that the GPU, not CPU, is working to encode the video (see pic).

But the CPU is still burning away at 90 Celsius and running at 81% utilization.

Am I missing any settings? How can I cool down my CPU further? Thanks!



[Attachment 79537 - Click to enlarge]

[Alwyn]

I just did a quick test: NVec H264 to 576p very fast, my 3060ti was on 100% and my i7 was on ~40%.

Your CPU load does seem high for an NVec encode, but the temp is the worry. Does it get that high normally?

I'd be checking the cooler app to see the liquid temp is going up as well. If it's not, the cooler might be defective.

[Subtitles]

I stopped using Handbrake because of the high temperature that I encountered while ripping DVD's. I have a GPU and i7 and liquid cooling as well.
I would suggest trying other applications until you find one that works better and cooler.

[The_Doman]

If you want to reduce the temperature you can also try to adjust the Turbo boost settings to less aggressive or even turn it off.
Those settings are normally hidden in the Windows power scheme settings but you can enable them.
Reddit: Important Update To PROPERLY DISABLE Boosting
Ctrl.blog: Disable processor boost mode to prolong your battery life

It is mainly referred to Laptops to prevent overheating/fan noise but it works just as well for desktops.
First try to adjust the Turbo boost mode to "efficient enabled" or "efficient aggressive" and see if this helps?


[Attachment 79551 - Click to enlarge]

[Arctic]

Thanks for the replies! Liquid cooling works well.
I wonder though why my CPU load is 80%. Read elsewhere that some of the encoding work (eg audio, demux) is still done by the CPU even though it is on NVEnc.

Unfortunately my Win11 doesn't show "Processor performance boost mode". Odd. (Tried to change my RegEdit to try make it appear, but it didn't work.)
I need to keep my Turbo Boost as I need the CPU to upsample music files, which requires heavy duty computing.

On a separate note, I changed the Handbrake setting to NVEnc 265 (instead of 264). CPU temperature cooled a bit to 70+C ... still sort of high, but better than when I set it to NVEnc 264.
As a bonus, the file size with 265 is also about 10% smaller

[The_Doman]

Unfortunately my Win11 doesn't show "Processor performance boost mode". Odd. (Tried to change my RegEdit to try make it appear, but it didn't work.)
I need to keep my Turbo Boost as I need the CPU to upsample music files, which requires heavy duty computing.

Did you follow the instructions from this blog/site: Ctrl.blog

Press the Windows key + X, right-click on either Command Prompt or PowerShell, and choose run as administrator.
Type/paste in the following command (in one line), and press Enter afterward.

powercfg.exe -attributes sub_processor perfboostmode -attrib_hide

After you’ve made the settings visible, you can find the new option in the Advanced Power Options dialog.

You not need to turn of the Turbo-boost, just changing the behavior already can make quite a difference.
I use those settings with all my PC's and specially laptops (no boost when on battery).
You can create a customized power scheme to quickly switch between settings.

[jagabo]

The problem is the GPU encoding is so fast that the CPU is working hard to keep up with the other processing (video decoding, filtering, audio decoding, audio encoding). I don't know if Handbrake has an option to use GPU decoding. Or if your source is suitable for GPU decoding.

[Arctic]

Did you follow the instructions from this blog/site: Ctrl.blog

Missed that. Yes, it works now! Thanks. Changed to "Efficient Aggressive".
CPU load now 70+% (down from 80+%), on NVEnc 265 10-bit
CPU temp is 70+C... I'm more comfortable with this level.

Or if your source is suitable for GPU decoding.

Not sure about that.

I don't know if Handbrake has an option to use GPU decoding.

Handbrake allows encoding using GPU when we select NVEnc option

Read elsewhere that the CPU still works even though GPU is used for encoding. Guess that why the CPU still runs hot. But at least it is now not "overly" hot at 90+C

[James Pous]

There could be other reasons, why your CPU is at a high usage.
Handbrake will use by default the decomb filter to check, if your video is interlaced or has artefacts.
Many of the handbrake video filters are used by cpu only. This could be the reason for the high CPU usage.
---
If you want to decrease the CPU/GPU usage, you can do the following steps:

The CPU usage you can change with the windows task manager.
You can right click on the handbrake program and select the used cpu cores.
There you can reduce the amount of cpu cores to get a lower cpu usage.

Furthermore there are several gpu tuning tools for nvidia graphic cards.
They give you the chance to control the gpu fan speed and some of them let you choose the gpu clock speed.
So you can reduce the overclocking or maximum Mhz.

[wade7575]

@Arctic If you don't mind me asking what's your exact CPU that your running,I have an i9 9900K with an old GTX960 card because I don't much and no matter what my settings are in Handbrake running the same cooler your running I never get above 50 or 55C and all my setting are maxed out.

[Arctic]

If you want to decrease the CPU/GPU usage, you can do the following steps:

Thanks James. Helpful tips

The CPU load and temperature dropped further also when I change the processor performance boost mode from Efficient Aggressive to Efficient Enabled. (When I started this thread, my CPU was set to Aggressive, which probably explains the high loads and temperature. Thanks for all the help here!

[jagabo]

Doesn't all that slow down your encoding?

Have you tried using a slower encoder preset? Of course, that will also slow down your encoding but you'll get better results along with your lower CPU usage..

[Arctic]

Doesn't all that slow down your encoding?

Have you tried using a slower encoder preset? Of course, that will also slow down your encoding but you'll get better results along with your lower CPU usage..

I don't encode a lot Speed not noticeable to me.
I used Very Fast... I thought that would trigger less CPU load.
I just tried Fast (instead of Very Fast)... temp in the 70sC, but CPU load seemed to have gone up to high-80s