Sudden hang, distorted pointer, performance extremely slow

Was editing a new batch of picks from a recent shoot, about 250 photos. Basic stuff. Was getting excellent performance with zero lag issues whatsoever, even with noise reduction. Working offline, syncing paused. Everything was fine. Suddenly, I'm having drastic performance issues. Screen flickering, pointer distortion, big hangs when loading the control panels for edits and spot fixing. Seems to be intermittent and I can't quite put my finger on the cause. The pointer will distort when I move it to different parts of the display, sometimes this is the grey window, frequently the menu bars (I cannot seem to screen capture the pointer, it disappears when I do a screen cap, so I'm attaching short videos I filmed on my phone). The menus will flicker when I pull them down. Task Manager shows a huge bump in resource use when the pointer is in this distorted state, but when I move the pointer somwehere else and it resumes its proper shape, the hang goes away. The only other piece of info I can think of is that at one point I had clicked the "auto" button next to the presets, and that happened somewhere around the period of time the hangups started, but I can't say for certain whether it was what started the problems, just that it wasn't too far off in terms of the onset.

This is getting quite frustrating, and I'm not sure what to do. I've rebooted several times and run all updates. I'm in the middle of a big project so I'm reluctant to do a reinstall. Help..? Thanks so much in advance.

-Kris

Lightroom Version 5.4. Machine is a homebuilt PC, Z87 chipset with an i7, 4770k with stable OC at 4.5Ghz, a 1070 Ti, SSDs, and 32Gb RAM. Runing latest version of Windows 10, and latest Nvidia drivers.