How to test if video card is bad?

Got a Tesla P4 off eBay sometime last year, and followed Spaceinvader's guide to setting it up. Plex saw it and it was transcoding, but then Plex locked up and I was unable to stop the container and had to reboot to be able to fix it.

Ended up removing the card from Plex settings and the issues didn't reoccur.

Recently wanted to try the card out again and set up Unmanic and grabbed a video to test transcode on it and same thing happened, Unmanic locked up and could not stop, kill, or restart the container. Rebooted and back to working. I assume if I try to transcode again it'll lock up again.