If send PC to sleep when its playback video(mp4) in browsers, after wake up, idle clock stuck on UVD State 450/1200 mhz, clock may go higher up to 860/1200 mhz but dont back to stock idle state 300/150 mhz. Only reboot PC fix this problem. Videocard in stock mode, not overclocked. Sorry for my bad english.
My card: PowerColor HD7850 (AX7850 2GBD5-2DH)
Driver: 18.3.4 (problem was on all version driver)
OS: Windows 10 Pro 1709 (problem was on 7,8,8.1)