AMD CPU locks up during video playback

[MR]

Final (I hope) update:

I installed the newest video card Friday evening.  It' s Gigabyte
NVidia GEForce GT 1030, a tad more expensive than the previous two
but, IMNSHO, worth it.

I had another lockup on the Max card Friday afternoon, from which I
was able to recover by ssh from my laptop, killing various apps shown
by top as taking up time.  None of them were super busy, but I killed
chrome, then VirtualBox, both to no visible effect (screen, k/b and
mouse fully frozen) and finally xfwm4, which returned me to the login
screen and all was, not well, but at least better.

I've been running the Gigabyte card through all the paces, including
long running background videos, mplayer, Netflix (Amazo coming up
tonight or tomorrow), and my VB Win10 VM running (inactively) on one
workspace I only touch when I'm using it.

Not a glitch.  Full 2k res on HDMI.  Smooth sailing so far.

Conclusion: it certainly appears to have been a mismatch on the video
cards with the M/B and CPU.

I posted reviews on both of the other card on Amazon.  I'll do this
one, too, after a fair settlement period.

I'll post if anything changes here - hoping to be silent for a long
time on this matter.

Thanks to all who brought their expertise to bear and helped in any
way, great or small.

Gratefully yours,

Mark