Did one o them auto OC things which got me to 3.77Ghz.
The UE4 compile time is almost exactly the same as my pre-BIOS update 3.5Ghz result (21.25 mins | 19.54 mins);
Light build of the same scene: 1:36 min total, 126 ms importing, 30 ms setup, 3.60 sec photons, 1:32 min processing, 0 ms extra exporting.