Is there a GPU stress test you recommend?  I am a bit worried that this computer, which was thrown together, may not have the capacity to handle a lot of heat.  But I guess I can monitor that for a while.  Also note that I have my GPU turned off from graphics duties–it’s not driving my X windows–but is available for calculation tasks.  I
So far, the system with the 435 driver seems much more stable, though I continue to run into problems less frequently.  So far, after a couple days of use, I had to reboot to get CUDA back again (same problem as my initial post here).  Also, after starting / stopping the debugger (and a suspend thrown in), the debugger says no gpu is free, even when I open an ipython console in the debugger.  However, when I open ipython from terminal, it sees the gpu.  PyCharm problem I guess.
Peter