Okay, I don't have enough context to really know, but while it's (always) good fun to laugh at audiophiles.. Could it be that the guy is actually experiencing an improvement due to actual real reasons?
Imagine: They're on a super low-end chip, feeding a bufferless DAC, and they're experiencing buffer under-runs, which cause really noticeable degradation ?
Imagine: They're using some API so wrong that it "works by accident" but only really when timings are "just so" ?
If I'm feeling charitable I could imagine they're perceiving interference differences because the DAC is internal integrated junk.
I've had thinkpads in the past that would output varying degrees of noise on the analog line+headphone outputs. It was highly dependent on what the CPU was doing, how much data it was moving around. It was kind of fun as a sort of audible system instrumentation while developing/testing software. The more optimal I'd get things, the higher pitched the noise became.
But no "audiophile" should be using such cheesy analog output from a computer... At least get some S/PDIF off to the fancy preamp.
I don't know about other laptops but I personally experienced a latent issue with all lenovo laptops (thinkpad & ideapad) where there is a short between the keyboard and the audio card - you could hear very faint static with headphones plugged in when there was no audio playing and I could even hear the static change when I scrolled my mouse - possibly because of how closely packed everything is.
I was thinking the same, especially as this is about optimizations.
Go back 10 years and many laptops had issues with cpu frequency scaling and sound quality. (Cheap components that would either start producing audible or em noise that would impact sound)
Imagine: They're on a super low-end chip, feeding a bufferless DAC, and they're experiencing buffer under-runs, which cause really noticeable degradation ?
Imagine: They're using some API so wrong that it "works by accident" but only really when timings are "just so" ?