I was on 7 for the last few months and installed 10 v1809 yesterday. Optimized windows as usual and undervolting of CPU and GPU put in place, my custom power plan and all!
And then I fired up my Ghost Recon Wildlands...
Surprise! my CPU temps peaked into low 80s and was in 75-80 ranges.
Now I was wondering what changed - other than me moving from 7 to 10...
Let me think... ah, I recall now. I upgraded my BIOS from 1.19 to 1.21. But then would a BIOS update mess so much.. didn't seem so likely.
And then I examined the power plan and saw that 10 added a hoard of new options not available while I was on 7.
I installed Park Control and toggled option in it to see all possible power options within the power plan and closed it.

Then started the new couple of hours of reading what these settings were n what they did, and then playing around.
Link here for anyone interested:
https://docs.microsoft.com/en-us/windows-hardware/customize/power-settings/configure-processor-power-management-optionsThe outcome was more towards my liking...
1. Task Manager - notice the CPU usage and frequency while I am on this forum typing this post.

2. Game temperatures for the same game Ghost Recon wildlands
Notice how the temps now are in 70 range, except for that little spike that pushed it to 75 momentarily. That's over a 10 degree drop!

Now coming to what i adjusted in power settings:

Major changes made:
1. Disabled processor autonomous mode
2. Reduced latency sensitivity hit from 99% to 0%
Performance wise, I did not notice any difference - my game was at a steady 60 FPS like it was prior to these changes.
Try these changes out, and see if they make any difference to you folks.