Dual logging locking up

[frogofpeace]

Not a huge issue, but I'm all about learning life skills, so I'm seeing this as an opportunity to learn how computers work (that's why I tell my wife I game, too).

I'm using the instructions here for running two accounts on NS4 at the same time:
https://soulforge.world/tiki/tiki-index ... e+computer

Running through Nvidia GeForce GTX 960M (I think the game's pointed to the right card - also have the onboard Intel graphics)
Windows 10
Windowed mode

The accounts log correctly, but after a few (10? 30?) minutes, one of the scrrens will "lock up" - I can still see the toon, it's still doing stuff, but dead mobs stop disappearing, new mobs stop showing up, casting animations don't run (although, looking from the other window, they seem to have fired ok), drops and placeables sometimes disappear, and things like doors and transitions don't work. Logging out and back seems to fix, for a while. It seems to happen randomwly on either instance.

When running two instances normally, the inactive window seems behind, in that a lot of actions that occurred previously all happen really fast like it's catching up. Kind of like what happens after a lag spike sometimes.

Any suggestions for how to keep this from happening? As near as I can tell, the method for dual logging above uses the same nwnmain.exe to run - I've tried copying the .exe and folders and running the two accounts from separae ones, but haven't quite figured that out. The game runs that way, but looks like this:

Picture2.jpg