All audio data is routed through a FIFO buffer before bing played back. A large buffer assures that no underruns occur (all audio is played properly) even under heavy load. The drawback is a long latency time when mixing multiple audio sources.
[HKLM\Drivers\Builtin\NvWaveDev]
"maxBufferSize" = dword:0x8000 ; Default size is 32'768 bytes
In a typical application for T30/WEC7 a maxBufferSize of 0x1000 is fully sufficient. This increases the chance of underruns, but decreases the latency to a level where it cannot be recognized anymore (by me).
When I set the registry that I taught, sound effects are played without delay even during movie playback.
After this, I will look a little about the influence of setting “maxBufferSize” to a small value.