almost 4 years ago - AndrewT - Direct link
DXDIAG is a program you run from a command prompt or the Windows start menu 'run' dialog box (or 'search programs' in Windows 7 or later). After running it will open a window and start collecting info with a progress bar in the lower-left corner. When it completes click the 'save all information' button and save it to a file then attach that file here.

Please attach your Documents/Paradox/CK3/pdx_settings.txt .
From your Documents/Paradox/CK3/logs/ folder, attach system.log , error.log


Please report the temperatures of your CPU and video (GPU)
1/ before starting the game up and
2/ after say 10 minutes' play.
If your PC's vendor has given you no way of reading temperatures, install
SPEEDFAN http://www.almico.com/sfdownload.php  
almost 4 years ago - AndrewT - Direct link
I think you can ignore those AUXTIN ones, but the GPU does have a problem.

Your settings should have capped the refreshRate/frame rate at 60, is that what you see with an fps counter?

If so your machine has a cooling problem. Clean out all air vents it has (compressed air cans are good for this). Make sure airflow to them is not blocked by anything like walls, books or whatever.
If that doesn't drop the temps enough, you probably have a faulty fan or a heatsink/thermal paste problem. You may need professional help at that point.