Litecoin miner crash with no apparent reason
Your settings look good.  If it was working OK with same settings for a while, then started acting up, either you have a software upgrade that's causing issues, or (more likely) you have a new/developing hardware issue.   

I had one doing the exact same thing last week (would run for a few hours and then reboot). I ended up reloading the os and then from windows to linux (bamt) and it was still doing the same thing. Under closer inspection, turned out two of the gpu card's power wires were burned straight through and had broken off (both yellow ones in my case).  Don't know how it worked at all with two missing power wires, but maybe it was getting some power from the motherboard and only needed the extra capacity under heavy load.  Either way, I replaced the burned out pciex power connectors and it's been running with no issues for a week now.