I am running some homelab stuff with NUC5i5RYH running ESXi. I wanted to know why everything showed up as 1.6ghz and not the 2.7ghz it should burst to. I got a reply from INTEL stating:
The Intel® Core™ i5-5250U Processor is an Ultra-Low power processor (because of the U at the end of the model).
Any U processor cannot disable speedstep which would have allowed me to run full speed, just an FYI to those wanting to do it! You will only get the downclocked speed.