Hey, sorry for the slow reply.
Audio > Realtek ALC8xx > With DSDT > ALC889
Plagued with problems at the minute:
• Freezes, finder dies, everything dies but the system keeps on running.
The hard shutdowns and restarts are playing havoc with my Time Machine drives 'invalid node structure' happens far too often, similar with my boot/OS SSD also.
I still have some artifact issues so I cannot rule a faulty card out yet, in all honesty I'm pretty sick of it if I could afford a decent Mac Pro replacement I'd do it without hesitation.
Did test a quad on a recent trip to London (Regent St store) and it scored a lot lower in Geekbench than this, around 9000, bet it's a lot more stable though.
If the problems continue I'll start split half searches to rule out the problem, first port of call will be another clean erase and install but no migrate from Time Machine, start afresh, a few apps at a time.