Going crazy: Rig crash

[revvv]

Hi guys,

I am really going crazy. I just bought a new PSU 900w: Antec HGC-900w. I was testing it on a rig with only 1 280x. It worked fine all day but when I came back home I found the rig off. I turned it on again and started cgminer. After few minutes the rig shutdown completely. The GPU temp is normal around 70degree. I am not sure if its the UPS.
The rig stays on for hours without problems but when I run cgminer then the rig just crashes. Something weird is the PSU fan is not spinning at all not even at startup, I am not sure its because its temp regulated.
Again the rig works fine for hours, it crashes after I run cgminer.

Thanks

export GPU_MAX_ALLOC_PERCENT=100
export GPU_USE_SYNC_OBJECTS=1

-I 13 -g 2 -w 256 --auto-fan --thread-concurrency 8192 --gpu-engine 1070 --gpu-memclock 1500 --gpu-powertune 20                               

[TheTribesman]

Try -g 1

[revvv]

So far so good but the hashrate is 550kh/s. Thanks!

[MisO69]

Increase thread concurrency. Try 11200. Keep raising it until you find the sweet spot.