I have a Asus ROG Zenith Extreme with a 1950X which is cooled by a LiqTech TR4 360 with its fans replaced by three Noctua NF-F12 industrial PPC-2000 PWM 120mm fans. So cooling is not an issue. For memory I have 32GB of G.Skill Flare X DDR4 CL14 running at 3200MHz.
My main issue is that even if I run a 100% single threaded load my CPU never boosts to 4.2GHz which the XFR range should allow. I don't even see the advertised 4GHz boost clock. Instead I see it around 3.9GHz. That is 300MHz difference on a build where I didn't save on the mobo, the PSU which is an AX1200i, the memory or the cooling. What could be the issue?