Windows 10 UI lags horribly when streaming webcam video
My system has recently started to lag when streaming video from my webcam. This manifests as: all UI windows are very slow to respond, and keyboard input is lagged. Examples: My web browser or text editor, which aren't using the webcam, operate slowly. As does the video streaming app I'm using: keyboard input is delayed and mouse clicks are very slow (4s+) to register UI events visually.
This occurs regardless of which video streaming app I use: BlueJeans, Zoom, MS Teams, or WebEx (MS Teams seems to be the worst, but my sample size is not great). I'm using the native Windows app for all (not streaming through the browser). With Zoom, the lag seems a bit less, and it tends to clear up for a period (2-5min) before recurring during a call (I use mobile phone audio to avoid losing my audio during these events). It generally takes 4-10min for the problem to occur initially after starting streaming.
Symptoms clear up when I stop streaming and close the video conferencing app, after a few minutes. In Zoom I often get this message while the problems are occurring: Low system resources may affect your audio quality. Try closing some applications to improve performance. Other streaming apps don't seem to notice a problem.
Notably when looking in Task Manager, CPU and RAM are not heavily utilized, so this doesn't appear to be a CPU overload situation. Notably also, this problem started in the last couple of months, and my system worked fine with this webcam since I bought it over a year ago.
I'm struggling at this point to find diagnostic approaches to figure out what's wrong and how to fix it. I would welcome any diagnostic suggestions or prescriptions for a solution.
System Notes: I'm on Windows 10 latest, on a Lenovo T480, drivers up to date. I'm using a Logitech USB C615 webcam. I've uninstalled and reinstalled the webcam drivers with no effect.
System specs:
- 8th Generation Intel® Core™ i7-8550U Processor (1.80GHz, up to 4.0GHz with Turbo Boost, 8MB Cache)
- 20GB Ram (currently/typical 13GB used)
- SSD system drive with 700 GB free
Solution 1:
Even with an I3 CPU, the Lenovo should be able to handle a teleconference. That said, there are a few things to try:
- Set the resolution of the webcam to less than maximum, 1080p. Try 640x480, for a start, and if that works well, increase resolution until the problem recurs.
- Look for other software that might be using I/O, as well as CPU and RAM. Clearly, the warning is
Low system resources. - Look for malware that might be doing the same. Perform a full scan with a different tool than your regular antimalware suite, e.g. free Malwarebytes.
Solution 2:
It appears that my machine was overheating in the GPU but not the CPU. This is on a mobo with an integrated GPU unit. I replaced the motherboard and problem persisted, so I believe this to be a general cooling problem with this model of laptop. I measured the internal temps and was able to confirm that the stuttering occurred when the GPU temps were high and did not occur when they were low. This explains why it took 4-10 min of video decoding for the issue to occur.
I was able to prevent the problem from occurring by throttling the CPU: the problem seems to be that when CPU activity is at a certain level, and GPU activity is high, the CPU overheats the GPU on this machine. Throttling the CPU prevented the overheating problem (but also made the machine relatively sluggish).
The way I throttled the CPU was using a tool called "Throttlestop" but I've read that it's also possible to prevent "turbo mode" by going to Windows Power Management and setting max cpu for all power modes to 99% (on battery, powered).
So, I ended up just replacing the laptop with a different model (one with an AMD cpu) -- notably the model was close enough in hardware that I simply swapped the hard drive and the OS (Win) booted into the new machine fine, and the problem does not occur on this new machine -- so I'm now confident that the problem was not software on the computer nor the webcam itself.