GPU Mining - cgminer crashes with higher intensity startup

[csun]

I'm running into a strange issue that I can't seem to find an answer for.

My setup:
Mobo - Asus Rampage II Extreme
GPU - 3x MSI 7950 BE
PSU - 1000W Corsair HX1000 (Which I guess is really 2x 500W PSU in one)
Windows + MSI Afterburner.

All 3 GPU are clocked at 1000MHz for engine, 1250MHz memory.
All 3 GPU are undervolted at 1.083V

I found my tc to be 22400.

I have MAX_GPU_ALLOC set to 100.

If I start up cgminer with anything other than the default intensity 8, it crashes after about 10 seconds. Haven't been able to get any debug logs because my monitor freezes for a while.

I can, however start at intensity 8, wait a few seconds, and then crank the three cards to 20,20,19 and have it run for 3 days straight (and probably longer if I didn't stop it) with no problems.


Anyone ever experience anything similar and found a fix for it?

[vm1990]

depending what other hardware you using could be a power problem id imagine with those cards overclocked you pushing 750w on the cards aline if not more
add a cpu 800-850 drives and power loss 900w not to mention scrypt mining causes extreme lag on the display so what looks like unresponsive could just be lag

i would get a watt meter and see how much is goung through the psu you might need a bigger psu or loose the overclock

[csun]

I'm fairly certain it isn't a power issue, unless my PSU can't handle the sudden ramp in current draw, but I don't think that's the case. This happens with 1 card running as well.