Hello. With 4 sticks I have random not booting problems on my Maximus XI Hero (with any ram settings the system may not boot sometimes, on my old z370 g gaming - no any ram problems), with 2 sricks everything fine, but with 2 sticks I have low cpu load when AVX stress tests.
For example LinX 0.9.3:
4 sticks: ~440 gflops
2 sticks: ~320 gflops
Of cource ram works in dual channel. With noAVX - no problems. Another asus z390 defect?
I bought another Hero XI and have the same problems lol.