Yup yup gpu throttling will definitely cause frame rate issues. This is good thing as is the gpu saving its self from experiencing demise! For the op had look through your settings and thankfully did before just suggesting checking task manager.

Have noticed you enabled 8x supersampling, a fairly demanding setting as you are forcing game to run at eight times native resolution. This works best on 2000/3000 series Nvidia gpus because the ten series lacks the tensor cores leveraged for this task. Try setting this to 4x or 2x or disabling and see if frame rate improves. If does not be certain to check task manager during the frame issues for insight.