Why does the sound lag in Ubuntu OS from operations with an SSD FS mounted with the sync flag?

Question

linux

Why does the sound lag in Ubuntu OS from operations with an SSD FS mounted with the sync flag?
In addition, in the Firefox 66 browser, scrolling of cached pages lags. At the same time, the priority of PulseAudio is the highest, and the processor has 2 cores, no more than 60% is loaded per core.

Answer 1

Because it is not necessary to pull synchronous operations where there is no need for them.