I'm having the same issue. I have a 2700X, 32 gigs of 3400 speed RAM & 2080 Super running Windows 10 Pro. I will start off with 60 fps & start running, after a minute my fps drops to 8-10-12. I have the most recent Nvidia drivers. It doesn't matter what render distance I have it set to or screen resolution (1920 x 1080, 1440 x 900, 1280 x 720) it will still drop. If I stop running my fps will go back up to 60 & drop again if i start running or flying.
I'm having the same issue. I have a 2700X, 32 gigs of 3400 speed RAM & 2080 Super running Windows 10 Pro. I will start off with 60 fps & start running, after a minute my fps drops to 8-10-12. I have the most recent Nvidia drivers. It doesn't matter what render distance I have it set to or screen resolution (1920 x 1080, 1440 x 900, 1280 x 720) it will still drop. If I stop running my fps will go back up to 60 & drop again if i start running or flying.