Ryzen 1800X boost with SVM enabled

I ran some tests with Ryzen 1800X and Asus Crosshair VI Hero board and it seems like enabling SVM in bios causes CPU to NOT be able to do 1 and 2 core boost.

With SVM disabled CPU easily holds 4.1 GHz when 1 core is under load (Cinebench single threaded). Enabling SVM the CPU goes only up to 3.6-3.7 GHz with extremely sporadic spikes to 4.1GHz.

Is this expected behavior? I wouldn't expect SVM to affect clocks (at least not if it's not in use -- just enabled).