Question / Help Game FPS drops when OBS idle

Hi all, First post, please forgive any newbie mistakes!

I've been very unhappy with Shadowplay and am attempting to replace it with OBS, but I've run into a problem. Put simply, when I run OBS, my framerate in game drops. This is without any sources or anything, just a fresh OBS install, sitting idle.

I have plenty of resources available, my PC is a 5820k with 16GB RAM and a GTX1070. If I sit still in a corner of an empty map to test it, My CPU sits at about 16%, memory is about 60%, and I am getting say ~137FPS in game.

When I start OBS, my framerate drops, by an amount depending on the canvas size/rate. For example in that spot, with the canvas set to 1440p (my native res) at 120FPS, my framerate in-game drops to ~122 (a loss of ~15FPS); With the canvas at 1440p 30 FPS, the in-game FPS drops to about ~128 (a loss of ~9FPS); With the canvas at 1080p30, the framerate in-game is down to ~130 ( a loss of ~7FPS).

Given that I have about half of this CPU to spare, I'd like to get my game recording to make use of it so I can maintain my usually high framerate, but before I can even set up any sources/scenes/settings etc, I already have this framerate drop. Is there some way I can avoid this? If it helps any, I'm an IT guy (just, graphics is not my field) so techy stuff is fine by me, don't spare the details :)

Log attached, of the run where I tested the above. Thanks in advance!
 

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  • 2017-08-02 04-16-00.txt
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04:16:00.793: fps: 120/1

I do not suggest using this FPS setting especially in 1440p. Also you need to post a log that contains a recording attempt. Record with OBS for a few minutes, stop the recording, then submit that log.
 

pootklopp

New Member
I am having the same problem, obviously with a different system and different numbers. Should I start a new thread or is it ok to piggyback on this one?
 
Well the problem doesn't occur when recording, it occurs when it is idle. Is a log from recording actually relevant?

I'm not necessarily planning to record 120FPS (although I'd sure like to! One of the reasons to use OBS is that it is possible...) but am demonstrating that the size (both in pixels and in framerate) of the canvas, is proportionate to the drop in framerate that I'm seeing even with OBS being idle.
 
Here is the log as requested. For this log I had to change my settings from those in the problem I am reporting of course, specifically I created a game capture source, and disabled the microphone source. Please keep in mind that any problems which may or may not exist with the recording aren't really a concern to me at this point, first I'd like to solve the problem of framerate loss with OBS idle.

Stats of note here are that I was getting a very steady 127FPS looking at this tree on an empty map. I alt-tabbed out of the game, started OBS, alt-tabbed back in and was getting 114FPS. I alt-tabbed back out and clicked 'Start recording', alt-tabbed back in, let it sit for a moment, during which it maintained that 114FPS, and then alt-tabbed back out and stopped the recording.
 

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  • 2017-08-02 09-55-35.txt
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Figured this out. The FPS drop is due to GPU load being generated by OBS - the reason this happens even when idle, is because of the preview. Even though no encoding is occurring, there is still substantial load on the GPU just to play back the preview. Minimising to tray brings FPS back up to expected ranges.

On this note, is there an option to disable the preview?
 
I should add, that the preview generates this load even when there is no source added and the preview is just a black square. I can't help but feel that there may be some inefficiency in the handling of the base canvas. Perhaps it uses GPU frame buffers or something??
 
You may also notice that your 30% GPU is not really as much as you think - For example if I run OBS, but no game, then I will see about 15% GPU utilisation - but this is at very low clock speed, say 200MHz. When I start the game it puts load on the GPU, increases the clock speed, and at 2GHz, that 15% is now more like 2%.
 
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