In addition to my last post, after just a couple of days of password cracking my super-beasty computer packed in. It seems the 4 uber GPU units decided to up and die which is not helpful when everything is GPU accelerated. Engineers turned up and we are firing on all cylinders again.
Interestingly I am now getting the full 20,000 passwords per second cracking speed that I was expecting whereas before I was only getting a fraction of that, I think there was something wrong from the start. As I look to my left a cracking job for a Police Agency is running at 18,000 per second, not too shabby.