@brucelee This shouldn't have anything to due with the lag/stutter issue you're experiencing, but you have a sound bug which you can tell by the SND/XACT warnings. This sound issue can result in unexpected behavior, including crashes. Simple fix steps are:
Windows key > type: Control Panel > Open > Sound > Playback > select the Device you use:
Configure > Stereo > finish configuration,
Properties:
Enhancements > Disable all enhancements,
Advanced > 16 bit, 44100 Hz,
Spatial Sound > Off,
Restart or Shift+Shutdown (not just Shutdown) of PC
If your headphones come with any applet/program, then you may want to disable that & try using the headphones without it. Similarly, if they use a USB or Bluetooth dongle to connect to the PC, see if you can connect directly without the dongle.
See this thread for further troubleshooting: https://forum.faforever.com/topic/4084/solutions-for-snd-error-xact-invalid-arg-xact3dapply-failed
