I'm also having the various "illegal memory, cuda devices busy, gpu restarting" errors everyone else is reporting with 0.4. Occasionally would get them with 0.3 as well but after 4-5 days. Now with 0.4 its guaranteed to happen within about a 26-27 hour period. Had the misfortune of not catching this on one rig for hours and losing precious uptime because of it. Luckily no GPU's were harmed.