Virtual machine freeze after update to Parallels 12+OS X Sierra [solved]

I'm using a Macbook Air Mid 2014 (Core i5, 4Gb RAM). Since 2014 I've been used Parallels virtual machine with Windows 7 installed, and it worked perfect almost 3 years in the configuration OS X Maverick + Parallels 10. Used mostly for software development needs and cross-compilation OS X+Windows.
About 2 months ago I decided to update both OS X and Parallels Desktop to configuration Parallels 12+Sierra. Also SSD has been encrypted.
It picked up all virtual machines without problems, but it appears that enormous CPU usage makes comfortable work in guest OS almost impossible. Project that compiled 5-7 minutes now takes 20-25 minutes to complete. Video in almost every player I tried is freezing as well.
Activity monitor reports CPU usage more than 200% (both cores I suppose), see screenshot attached.
I've heard about an issue with external drives that could slow virtual machine down, but for me it does not affect performance at all, it still consumes CPU with or without external drives attached to the virtual machine.
Could it be software issue? Or related to full-disk encryption?

 

Report ID is 178265817
Thanks

 

@YuriC, can you please make and post here a screenshot of Task Manager inside Windows with top consuming CPU processes.

 

Actually here it's not as huge as reported by OSX Activity Monitor. Greatest consumers are devenv.exe (Visual Studio 2015) and cl.exe (while compiling). In the moment of screenshot devenv.exe is actually unresponsive

 

According to problem report there's no evidence of any issues from the virtualization side. Guest processes of Visual Studio produce the real load of CPU: if you have two Windows processes consuming 50% CPU each this will result in ~200% CPU usage of virtual machine on Mac.

 

Maybe it's real, but it's unresponsive all the time while compiling is in process. In previous configuration, OSX Maverick + Parallels Desktop 10 it was normal.
I will try to downgrade and reinstall the system without full-disk encryption so that to compare, I will provide results here.

 

The reason was full-disk encryption. After reformatting SSD it works fast in the same configuration (OSX Sierra + Parallels Desktop 12)

 

Downgraded to Parallels Desktop 10 as well

 

Yeah, after downgrade to 10 performance back to fast, as it been before
I'm not sure whether encryption significantly affected it, but I also decided not to do it