After some time testing my system speed I am back to Windows 7 Professional. Several reasons :
- Incompatibility of my integrated graphics with Windows 10. Needed to use some third party fix for being able to bypass WDDM
- Real feel that my system is more responsive
- No Avast freezing problems and improper disablement of the Windows Defender in Windows 10
- Proper driver installation of my AHCI bus which made +70MB boost in read/write performance of my SSD
- Personal feeling of having more control over the OS
If I had newer laptop it would work fine with Windows 10, probably, but since Intel decided to leave us without the proper drivers for Intel GMA 4500 MHD and a 1/3 of the chipset, I had to make this move. I probably won't come back to Windows 10 until I buy a new laptop.