Would you...

[GoogalyMoogaly]

Stick with 16GB 8Pack DDR4 3600 CAS16 or mix that with 16GB DDR4 3600 CAS18 to have 32GB?

Would it even work mixing RAM like that? I'm not sure how temperamental Z370 was/is with mixing RAM.
And if it did work, would it be worth, presumably, running at lower CAS to get 32GB?

 

[GoogalyMoogaly]

It might be alright, it might not. Same thing with mixing RAM on any platform, tbh.


What is your usage of the PC?

If you're running out of memory right now then yes, you're very unlikely to notice the timings in games (a few fps at most), but if you're running out it can have a big impact in overall smoothness and especially the stutters & lows.

I was playing Crusader Kings 3 earlier and during some combat it was getting almost unplayable and I noticed my RAM usage was really high in Afterburner, possibly capping out or very close to.

 

[GoogalyMoogaly]

What I didn't make clear was that I already own both sets of RAM, the Lexar is just sat around in a box.
But I don't want to install them just to find it makes the system unstable.