GPU not registering in Hashcat

[AyKay]

The main problem is that the cards are registering with the OS (Ubuntu server 16.04), but not with Hashcat. 

We noticed this issue last Friday when we were running tests. We had 4 cards successfully running, drivers are all good. We saw the output, we had 4 cards. Then we started noticing that the output had changed and we only saw three cards functioning. We decided to restart the box, when it came back up we ran "lspci | grep VGA" and we got 4 cards. However, when we run Hashcat -b(or any operation, -b is just a faster test), the operation hangs and we simply cannot kill the process no matter how elevated we are. 

If you have any questions, feel free to ask. I am fully aware that these card just might be fried, but I just want to know what else can be done. I just find it weird that the OS knows there is a card and registers it correctly but Hashcat won't anymore.

[epixoip]

Going to guess that you are using risers?

[AyKay]

Going to guess that you are using risers?

Yes. 4 cards and risers. ASRock X99X motherboard, 2x 1200w PSU, 64gb RAM, 512GB SSD. 

Hope that is helpful.

[epixoip]

Knew it. Your risers are certainly to blame. If you're using the USB-style risers, get better quality USB cables and ensure all of the connections are firm and properly seated. If you have the ribbon style, you might have a short in one of the wires.

[AyKay]

Knew it. Your risers are certainly to blame. If you're using the USB-style risers, get better quality USB cables and ensure all of the connections are firm and properly seated. If you have the ribbon style, you might have a short in one of the wires.

Perhaps, I just think that it is odd that the OS picks it up but not Hashcat. Regardless, that seems to have been the issue. They are all reading after a good jigglin' and re-seating.

[atom]

Hashcat only can see what's registered in OpenCL. You might want to check your OpenCL installation (done by the driver) or use a different OpenCL program to compare.