OpenGL "lost connection" error code 7

Game crashes at seemingly random intervals.
New launcher gives these messages:

Client> AL lib: (EE) alc_cleanup: 1 device not closed
Game ended with bad state (exit code 1853227064)

Power management disabled for video card, still getting crashes.
Increased java stack size to 1-3G still encountering crashes.
<shrug>
Minecraft is unplayable