Overall Review: I've had these for over a year now in my ASUS Maximus X Hero (Wifi AC) Motherboard with 8700K CPU, bought this RAM kit specifically because it's one of, if not the fastest 16GB kit that's approved to work with this board at advertised speed. Would give errors in overnight MemTests at 4000 Mhz and crashed Windows 10 once or twice, once while idle (I know things run in the background, but memory load was low), so I dropped to 3800 as most reviews suggested and it's much better. Upgrading from 3000Mhz Corsair Vengeance that started giving errors, I've noticed overall FPS improvements (anywhere from 5 to 20 average FPS depending on game), so the extra speed does help. Since I see a G.Skill rep has responded to most reviews, hopefully he can guide me to which specific tweaks in the Asus BIOS can get me a stable 4000Mhz since this Motherboard is on the QVL.