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.
This is the new solvers, and I change them, in search of a way to make them better. So yes, every new version can be more or less stable, sorry for it guys. I continue this work until a satisfactory result is achieved.
On the intensity, it does not work right now, due to many solvers it will be completely changed and applied in the next version.
For everyone: I read this topic and see the errors that you posting here, so thanks for that, it really helps.