Litecoin miner crash with no apparent reason I have a machine with 1 R9 X280 running on Intensity 13. It ran for 2 weeks with no problems, and now it's been crashing every day, or even up to 4-5 times a day. (Crashing as in  rebooting with no actual reason in Event viewer.)
The card is running at 73-76 Celsius; it is in an open case.
I tried disabling the CCC, but that didn't help.
What can I test to look for the problem? It is a brand new computer.
Details
CGMiner 3.7.2
Mining command:
cgminer --scrypt  -o x -u x -p x --gpu-platform 1 -I 13 -g 2 -w 256 --gpu-memclock 1500 --gpu-engine 1080 --gpu-powertune 20 --thread-concurrency 8192 --auto-fan --gpu-fan 30-75 --temp-cutoff 90 --temp-overheat 85 --temp-target 70
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.