Is there any significant benefit to 1866+ MHz RAM? Would one see any major changes after making an upgrade from 1333 MHz (inb4 hurr) to 2133 MHz?
all my research on this amusingly controversial matter has shown that performance gains are REALLY highly circumstantial; only RAM heavy software or an appropriate upgrade to your CPU would fully bring out the performance gains of faster RAM. Other than that, it's gonna be a dimishing returns scenario for 99% of users.
TL:DR; unless you're doing heavy MATLAB 24/7, then no.
>there are people on /g/ who are unironically using APUs
I can't speak for the people you replied to in your first post, but I'm not using an APU except for in the media PC I built for my parents.
If you want a compact system that's adequate for pretty much any everyday task they're fine, and higher-speed RAM is known to improve gaming performance with APUs.