could you try to add this line, in your Tennis.ini (or the .ini of your Profile), under [Game] :
TimePolling = 1
then save it and check what happens in game, then close game, then change 1 to 2 and save it again & launch game again, and tell me what is better..?
Also, display the FPS (from "Misc Options" menu), and tell me if it's much different from 60 or not.
Alternatively, turning off your CPU speedstep should fix the issue.
The line "TimePolling = 0" should be already in the .ini , so change it instead of adding a new one.
== Mana Games ==
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