Bug Report 10% GPU Usage without a szene, up to 30% with only browsersource and gif

[Softwerker]

Greetings,

I noticed last week that my stream started to stutter randomly for the viewer but OBS did not show any skipped frames. When I opened the Task manager to check CPU and GPU usage I noticed that OBS is taking up to 30% of my GPU even though I am encoding with x264.

I have tested a bit today and noticed that even without any szenes in OBS an nothing to display the usage hovers at 10%


When I have my usual break screen up (Text, Gif in the Back, pictures and two browsersources) it even goes up to 30% without recording or streaming at all.


I have a GTX 970, reinstalled the drivers as well as a fresh installation of OBS. I have no idea why OBS is wasting so much resources in an idle state. Especially when streaming ARK or similar games, i do need those capacities.

 

[macharborguy]

The GPU is used to composite the scene into a flat frame that will then be sent to the encoder (either CPU x264 encoder or a GPU encoder). The more content that is on the scene, especially animating content, the more the GPU has to do to composite the frame.

As an example, my starting scene (which can be seen at the very start of this video ( https://www.twitch.tv/videos/233032320 ) uses about 40% of my GPU, which is an AMD Radeon HD 7950.

The R&D logo at the lower left is a browser source and acts as our alerts. The big R&D logo and "Going Live..." text is also a browser source. The animated images and background are all individual WebM videos playing on a loop. There are also many other browser sources and such that are either off frame, hidden or with an alpha level of 0 (fully transparent).

When I switch to my gaming scene (skip to about 25 minutes into that same video), my GPU usage can jump anywhere from 45% to 75% depending on the amount of detail and action on screen.


That being said, if your scene was skipping for viewers, but you did not experience any skipped (cpu couldn't handle the load) or dropped frames (upload speed couldn't handle the load), then it could be something else going on down the line between you and Twitch or even on Twitch's end (I assume Twitch, though you didnt expressly say which service you stream to)

 

[BK-Morpheus]

As macharborguy already said:
OBS will render you scene via GPU, so depending on the content and setting (scaling, filters, framerate etc.), the GPU load will vary.
Also keep in mind that that GPU percentage is relative to the actual GPU clock.
So in Desktop/2D/Idle the little GPU load of an empty OBS scene will look pretty high (10-30%), although it is not. The GPU is clocked down in idle mode, therefore a small load will cause a high percentage of load.
In Full 3D GPU clock, this percentage will drop.

Animated/Filtered sources (especially browser sources) will cause higher GPU load and in the screenshot I see a huge load of sources.
On my GTX1070 I have 30%GPU load in Idle with an almost empty scene (webcam+wallpaper) in 1440p scaled down to 720p.
This load drops to 4% (technically the load is not dropping, but the percentage is), when I force my GPU into 3D clock boost.