Question / Help Trying to troubleshoot sudden bandwidth usage increase

[surc]

I'm having some frustrating issues with bandwidth and cpu increase, and I'm hoping maybe somebody else has some insight.

I had a configuration in OBS that was working solidly, bandwidth usage and CPU usage were balanced to stay just in the 'playable while streaming' range. All of a sudden, last week, OBS started using an extra 300kb/s or so of bandwidth, and an extra 10-20% of CPU, without my having changed any settings. I spent multiple weeks testing and confirming that even with spikes, it stayed within the acceptable range, so I have no idea why it would suddenly be higher.
I've been trying to troubleshoot it, and it's driving me crazy. Decreasing the quality of my stream in small chunks lowered the *low* point of the bandwidth usage, but as soon as there was anything actually going on, it spiked *even higher* on the high end (cpu usage did lower by a couple percent). I've been keeping an eye on my resource monitor to check what's using my bandwidth, and it is definitely OBS, not some other application, or windows itself. (Specifically, it's the OBS connection to reserved.justin.tv, which I assume is just my stream).

I've attached a log from me briefly hopping on stream again to test this morning, I don't really know how I can fix this from my end. I'm kind of tearing my hair out over this, as I don't know what else to try, and I'd really prefer to avoid having to lower my stream into 'completely unwatchable mud' quality territory.

 

[sam686]

Check for CPU throttling, slow down, and overheating using CPU-Z and HWMonitor. CPU slow down may look like OBS is using far more CPU usage and might be frame skipping.

The CPU usage of x264 encoder will go up a little during high motion action, compared to only a black screen or no motion. Some Webcams have some noise that causes x264 to use a little more CPU. Maybe change x264 preset to very fast for less CPU usage at a small cost of quality.

The bitrate may go up and down a little for good quality key frames. Reducing buffer may help bitrate stability at a cost of poor quality pulsing video.

 

[surc]

Hey, thanks for the info and suggestions! I played around a bit, and reducing the buffer was very helpful (And in fact, may have been where the issue was, as it appeared to be higher than I remembered setting it). I was able to tweak it somewhat, so while it's still not where it was before, it is much more playable without much of a decrease in quality.

 

[surc]

It looks like I'm likely now having some CPU throttling or slow-down, weirdly enough it *doesn't* look like my CPU is maxed out any more, I did up the preset to very fast for less cpu usage, but despite reporting plenty of left-over CPU on my various ways of monitoring it (my entire second monitor is essentially filled with monitoring tools at this point), I'm still getting some serious fps slowdown in-game. I'll update if I figure out what's causing that/how to get around it.

E: and no, the monitoring tools aren't what's eating up CPU, I've checked that too :P

 

[surc]

Hm, so I just tried recording a video instead of streaming it, and OBS's CPU usage went from 45-55% of my CPU to 20% of my CPU. I'm theoretically using the same settings for outputting video as for streaming it, anybody have any idea why streaming would be using twice as much CPU?