It's hard to see how a lower refresh rate could possibly make the games stutter more. Did you try the same thing with the other affected games? What actual fps are you getting in the games when my suggested settings are in use?
Then, make a new Windows user on this machine and log into that. Disable everything you can in the Windows Startup settings and reboot. Is it any better?
If not, install and run the free utility Speccy. Send its output to a text file and attach that here please.
Then, make a new Windows user on this machine and log into that. Disable everything you can in the Windows Startup settings and reboot. Is it any better?
If not, install and run the free utility Speccy. Send its output to a text file and attach that here please.