Thanks for the suggestions. It's a brand new system (less than a week), but it looks like there is a GPU driver update which I will try. DirectX is latest (12).
I know about caching and the green line. Note that a long time to cache is really THE issue and most intense processor usage if I try to load the big files into VideoPad. I do clear the cache before starting. But caching two or more big files takes so long that it is really unmanageable. I can wait several minutes (or longer) for caching to happen, then try to edit. But then changes like adding an auto level effect to the video tracks sets off another cache which I have to wait out once again. And each bit of editing just seems to make the re-caching happen slower and slower until it more or less just stops responding and caching never finishes.
I explored proxy editing, but wouldn't there still be a long wait and possible no-response on caching when the big files are swapped back in?
The long cache time using the big files is also why it is practically impossible to generate and back up to folder the project I want to create. I can do such a back up with a second-best project created with converted, smaller video files, if that would help make things clear.
Again, the problem is caching time for 2 large 4GB files plus two 2GB files at 60fps and a high bitrate as well. Caching just takes forever. And once a number of edits (splits for transparent bits, overlaid images on another track, etc.) are in place it seems like caching slows even further to an impossible crawl while driving the processor at 100%.
P.S., I'm running the latest version of VideoPad, just downloaded Friday.