Windows 10: Encoding Videos slowed down significantly after Creators Fall update

I often do video re-encoding for 4K Videos to reduce their ridiculous sizes that can reach up to 30 GBs for 90 minutes .

Usually it took 24 hours to convert a 1 hour 4K movie to H265 2K (I7 CPU + NVIDIA Acceleration) , I know is too much but still , I have seen worse results on lower specs (I3 CPU + No Acceleration may take well over 5 days) .

Now after creators fall update same videos and encoders , I might get at best 20% of encoding per day (Checking on I3 and I couldn't do an estimate as it never finishes)

I did try to update my drivers to latest and even downgrade to earliest but no use ..

Any suggestions ?

What software are you using to do the re-encoding? I use FFmpeg and the Fall Creators Update has made no difference.

Admittedly my machine is a lower spec than yours and my videos are not 4K, though.

I use either Any Video Converter or Avidemux all other packages I tested were struggling to deal with 4K videos or H265 or Hardware Acceleration wasn't supported by , I still don't think its an encoder software issue , even VSDC encoding slowed down for me too .