Bitcoin mining is so last year. Put your expensive GPU to use cracking passwords.
Kyle Rankin
2012-05-15
http://www.linuxjournal.com/content/hack-and-password-cracking-gpus-part-i-setup
...
Then Bitcoin tanked. That's okay though, because I hadn't gotten around to building my mining rig yet, and what's more, I found an even more interesting use for Bitcoin mining hardware: password cracking. Bitcoin mining and password cracking are quite similar operations, and a GPU can crack passwords much faster than a CPU or even a small cluster of CPUs.
...
Bitcoin mining is no longer profitable.
...
It turns out that cracking passwords is a lot like mining Bitcoins, so the same reasons GPUs are faster for Bitcoin mining apply to password cracking.
...