# Scene rendering via CPU?



## BK-Morpheus (Oct 8, 2017)

It seems that the scene rendering in OBS takes ~10% GPU load on my GTX1070 and I wonder if this could be improved (maybe by giving us the option to render the scene via CPU instead of GPU).

Minimizing OBS or disabling the preview will not lower the mentioned, additional GPU load. Only closing OBS will reduce my GPU load by ~10%.
In my scene there is the game capture, the webcam with chroma key filter and a scrolling text.


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## Harold (Oct 8, 2017)

It can't. CPU based scene rendering will take a LOT more system resources.


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## c3r1c3 (Oct 8, 2017)

So you would rather OBS use 40%+ of your CPU (assuming you have a 16-core unit) to render a scene instead of 10% of your GPU?


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## BK-Morpheus (Oct 9, 2017)

c3r1c3 said:


> So you would rather OBS use 40%+ of your CPU (assuming you have a 16-core unit) to render a scene instead of 10% of your GPU?


Could be handy in some situations, yes.
Example: ARK Survival Game. Uses only ~3 of my 16 cores and the x264 OBS recording at fast, faster and very fast leaves a lot of headroom on my CPU, but the GPU goes from ~75% (GPU load with only the game running at 60fps limit) to 88-92% with OBS opened and at that point, my OBS frame output will less than the drawn frames and I can see some stutter in the video and preview window, although log shows now lagged/skipped frames.

```
00:37:56.838: Output 'adv_file_output': stopping
00:37:56.838: Output 'adv_file_output': Total frames output: 864
00:37:56.838: Output 'adv_file_output': Total drawn frames: 934
```
Not sure, if the difference between drawn frames and frame output is really an issue, but there is micro stutter in the Video+Preview, and no lagged or skipped frame entries.

After a lot of testing, I randomly got one moment where preview and video were absolutely smooth. As soon as I closed OBS and started it again (with the same settings and the game still running), the stutter was there again.
It's not stuttering a lot and not the whole time. It looks a little bit like the stutter you can get when recording with 60fps and running the game with 64fps (or other values out of capture sync).


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## c3r1c3 (Oct 9, 2017)

That's good to know. Jim has considered it on a few occasions, but all of us always say "Do it someday, but not now because there's other things to be added that are more important." So the more people who speak up about needing/wanting it (in general) the higher up the priority chain it can go.

Using Studio mode can chew up more GPU, so turning it off when you don't need it and turning it back on when you do need it can help.


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## BK-Morpheus (Oct 9, 2017)

Never used studio mode, but thanks for the info.
At first I thought the additional GPU load will decrease when I disable the preview, but sadly that's not the case.
Not sure how much load a comparable scene is generating in other capture programs or which sources/effects generate the most load (already uninstalled Xsplit trial version, but at least the preview in Xsplit is smooth without stutter).


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