HI Billa, sorry I'm pretty stumped. The main difference between V3 and V4 is that V3 used Direct3D9 while V4 uses Direct3D11.

I tried doing some research on your particular card and it seems that there are similar problems reported:

https://www.nvidia.com/en-us/geforce/forums/discover/283079/major-stuttering-with-all-games-rtx-2080/

Are you on a laptop? Seems to be a problem where it's severely throttling the GPU clock speed when it hits a certain temperature.

There are some settings mentioned in the thread you could try, like running the app in Windows 7 compatibility mode by right-clicking on the app shortcut / Properties.

You also might try shooting some compressed air through it to clear out any dust if that is preventing it from being cooled well.

I don't know why Direct3D9 would be unaffected, maybe it somehow doesn't support the thermal throttling or something like that.

- Michael