You still need the motherboard Realtek drivers if you're not using dedicated audio hardware (soundcard, external DAC, etc). Sadly, many games refuse to install or run if they don't detect audio, so you can't have a truly "silent" PC, lol.
The extra ASUS audio softwares - Sonic Radar, etc - are not essential drivers, they provide additional features or functionality but aren't strictly required to make noise. I always check out all the ASUS software which comes with my ASUS products, but a lot of it I find isn't necessary or even very good (compared to alternative softwares). It's got the snazzy ROG look and style, though, great for impressing people haha.
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[/Korth]