Question / Help Lower encoded Frames if Game is in Focus

[RyoNara]

Hi,

I have recently upgraded my PC and finally have found some time to figure out
my stream settings. I have read on these and other forums for guidance and
set up my stream accordingly - at least I believe so.

But I have a problem that is seemingly disconnected from bandwith and/or CPU usage.
If I am streaming (1600/900, 30fps) my stream looks fine, with minor stutters and/or
pixelation. Those I tribute to my amazing ~800kBit upload (thanks Germany!) and
are not the problem I want to solve here.

So stream is running fine as long as I do not have the game (SCII) in focus - as in I
have selected any other window (win7), OBS is claiming 0 dropped frames, 800kbit up
and 30 FPS. Great. CPU usage varies between 50% and 60% on the "veryfast" preset.
I can setup my windows so that I can see my, not yet focussed, SC2 fully and the OBS
FPS next to it. As soon as I click into the window - wich does not change my CPU usage
or my ingame FPS or anything that is displayed on my screen or on the resulting stream
- the FPS that OBS encodes drops to a whopping 8 FPS.

I have tried to change Bandwidth, Encoding preset, resolutions and FPS settings to all
possible extreme values - both high and low - and always hit the same result.
As soon as I switch to the game the encoded FPS drop drastically to around 8 FPS.

Now my only guess here was, that windows somehow throttles the process as soon
as it is considered in the background, but changing process priority or designating cores
does not have any significant impact too...

I am at a loss - can anyone help?

i5 4670k
8GB RAM
Windows 7

Thanks,
RyoNara

Mod edit: Moved log to pastebin - http://pastebin.com/rPwjvk7S

 

[Sapiens]

Based on the log, the issue appears to be that your GPU is terrible and OBS is having to use it in compatibility mode. The GTS 250 was a mid-range card ~6 years ago. There's not much you can do about this aside from downscaling your stream a lot, or getting a new GPU more in line with the rest of your system specs.

 

[RyoNara]

I hear you, but how is it that this only happens as soon as I focus the window?

SC2 seems to be running at full FPS even when the window is not in focus, so the load on my GPU
should be exactly the same? The Output stream shows SC2 in all its glory with full FPS too.

I cannot see a difference on GPU-Load from switching the focus to a already fully shown window?

Edit.:

Following your suggestion, I again tested to drastically downsize the resolution and found that
the effect is indeed lower at very low resolutions, so maybe the graficscard is in some way
responsible for the effect. I still dont understand the effect though, as the exact same picture
is produced and streamed if I have the focus outside of the window.