Quote from: grndzero on October 28, 2011, 04:40:31 PM

Some thoughts:

Post your motherboard, cpu, power supply specs, video card model so people with them can offer insight.

Definitely should've put this info up front. Here it is:

mb: GIGABYTE GA-990XA-UD3
cpu: AMD Sempron 145
cpu cooler: Cooler Master RR-B10-212P-G1
Antec HCG-750 750W
ram: 4GB crucial
ssd: patriot PT232GS25SSDR 32GB
1x5970
1x4830

All above except the 5970 and 4830 are new. I got the two cards from different people and I can reproduce the problem with either unplugged from the mb, so I don't think either card is defective.

Quote from: grndzero on October 28, 2011, 04:40:31 PM

Check which screensaver Unity is trying to use, on 11.04 it should just be a blank screen, but if it's trying to use something else it could be locking up the driver when it kicks in.

This is a fresh 11.04 install, fully updated. I've never logged in on the gdm, only on terminal.

Quote from: grndzero on October 28, 2011, 04:40:31 PM

Some people have said that leaving a mouse plugged in can cause problems if it is constantly seeking it's position on the screen. Make sure the mouse isn't near the edge of the screen or try unplugging it.

Thanks for the suggestion, but no mouse here.

Quote from: grndzero on October 28, 2011, 04:40:31 PM

Are you setting fan speed and checking temps?

Before I attempt to start the miners, I set the fan at 50% and I have two 'watch' screen sessions running:

Code:

aticonfig --odgt --adapter=all

and

Code:

aticonfig --odgc --adapter=all

Both commands work fine. Temps have never been above 90 and usually in the low 80s. When I start the miner, the loads on the GPU are 0%. I have tried this on both phoenix 1.48 (using either poclbm or phatk) and poclbm, result is the same. When the miner hangs, the machine works fine and CPU shows minimal load. When it is running, I've gotten about 810 M/hash out of this setup.

Quote from: grndzero on October 28, 2011, 04:40:31 PM

What power supply are you using and what is it plugged into? You should probably have a minimum 650 watts for this machine.

I don't think it's a power supply issue. Today, I unplugged the 4830 but had the same issue with a single 5970. I've had the problem with the box plugged in at home and at work.

Quote from: phorensic on October 28, 2011, 05:17:04 PM

I found the guide in the cgminer documentation extremely useful on setting everything up. If you follow it step by step you should have problems unless you have a hardware problem like others are mentioning. Oh and make sure your fan speeds are set to manual above 65%. Even if the card reports low temps the VRM's could be frying from low air movement across the entire PCB. Causes a lockup within 5 mins for my cards if I don't set the fan speed high enough.

Thanks for the suggestion. I have gotten this setup running well and have kept a pretty close eye on the temps (monitoring both the GPUs and the CPU/MB temps). When it runs, it runs fine (for days). I am going to try reinstalling everything next to make sure this isn't the problem.