I have NVidia 980Ti video card. After upgrading a driver version to 388.31 and newer, I have just horrible performance in Unreal Engine. FPS jumping from 20 to 90 on empty scene without any reason in editor itself and PIE, VR is a slide show.
But if I roll back to NVidia driver 385.69, then I have stable 90 FPS everywhere. Does anyone have that problem?
Try uninstalling Geforce Experience but keeping the latest driver. Some people have been having issues with Geforce Experience specifically causing frame rate issues.