Just curious.. have these random KPs always happened or did they just recently start?
For me, and I know this doesn't really help much, but I had the exact same random freezing issues with my Gigabyte Z97 / 4790k from the moment I built the system. It was so random I figured it was a hardware failure (memtested fine / tried diff ram, diff PSU, went igpu, etc). I ultimately replaced the motherboard with a Supermicro z97 and things have been fine.
There were a lot of posts about Gigabyte z87/z97 issues back in the day.. just wasn't a good platform at the time.
I see you have a working 4790k system.. Asus? Definitely wasn't the cpu that was the problem.
Kinda funny, I'm also sporting a Z390-A Prime... rock solid. Nothing like the old Gigabyte.