290x Stops Cracking and Hangs OclHashcat

[epixoip]

Those 290Xs will draw around 320W on NTLM brute force, so your GPUs alone are likely pulling around 960W. Doesn't leave much power available for everything else in your system. Plus that's a pretty low-end power supply, so I'm not sure how well it handles cards that violate the PCI-e spec (as most high-end AMD GPUs do.) It may not like pushing more amps than its rated for.

I would start by removing the --powertune-enable switch from your command line, and use od6config to underclock the GPUs and de-tune PowerTune.

Code:

od6config --set core=975,power=0

That should help until you can buy a proper PSU for your rig.