I haven't followed the whole thread but it seems to me there's some mis-representation about modern computers. Many statements like "It's almost impossible to overlaoad modern computers" or "if your computer gets too loaded to handle audio you need a better computer", or whatever.
If you ask a computer to work it will typically work.. as hard as it possibly can, 100%, at least with one CPU, until it gets the job done. Sure if the job takes 50 microseconds, then that doesn't bump up the apparent load average because that average is calculated over some longer time. Of course the task scheduler may limit a job or at least allow other jobs some of the time, and some process are I/O limited instead of CPU limited, but all that said it's not even remotely difficult to get a modern CPU core to spin at 100% for 50 milliseconds doing even ordinary tasks, but especially if you're doing something like.. oh.. for instance... audio compression, or even more so AV compression which is an ENOURMOUS computational task and something quite reasonable to have your A/V computer doing!
What you do hope is that the audio itself is a very tiny load compared to everything else going on, and that your process scheduler is kind enough to give it the microsecond or so it needs before its buffer runs empty. A bit of googling on windows scheduling reveals that windows workstations allow foreground processes to hold on to a CPU for 6 quanta, which seems to equate to somewhere in the ballpark of 90ms! That's 90ms before anything else other than maybe an interrupt can do anything. Multiple cores sounds good, but if one process on the same core as the audio does that, and you have a 50ms buffer, then it seems like a problem to me.
I'm almost surprised it works at all and I'm not an expert on the windows scheduler so I'm probably missing something, but at least it's certain that scheduling matters, at least if done badly, and I'm not surprised if improvements are possible. I think the rep said this targets clicks and pops, not dull highs, and muddy lows. Sounds about right.
Disclaimer, regarding audio, I have no idea how much of the work is offloaded to the soundcard itself using direct memory access