Quotidiano Audio is growing audiophile online media in Italy since 2012. This software review was written on 8th April 2016 but I discovered this review only recently so forgive me for not finding you sooner. This review is written in Italian so I’ll copy the translate core messages here.
Looking more specifically, Fidelizer Pro v7 reduces latency, improves the performance of the clock, optimizes MMCSS (Multimedia Class Scheduler Service), no island-sound processes on a single core, run the audio player software with the highest possible priority, optimizes the kernel timers and audio files priorities; Some of these performances are unique in their kind (= software competitors do not have all these features).
You can do all that manually intervening? Probably yes, but at costs of several sleepless nights and probably not with the same results.
And here’s the original message in Italian.
Andando più nello specifico, Fidelizer Pro v7 riduce la latenza, migliora le prestazioni del clock, ottimizza il MMCSS (Multimedia Class Scheduler Service),isola processi non-audio su un singolo core, lancia il software player audio con la priorità più alta possibile, ottimizza il timer del kernel e le priorità dei file audio; alcune di queste performance sono uniche nel loro genere (=software concorrenti non hanno tutte queste funzioni).
È possibile fare tutto ciò intervenendo manualmente? Probabilmente sì, ma a costi di diverse notti insonni e probabilmente non con gli stessi risultati.
The reviewer Massimo Garofalo is also the founder of Quotidiano Audio and is quite knowledgeable about computer audio so I recommend to read full review for better understanding about computer audio.