Hello everyone!
I have sent an email to international support about my issue, but I figured it would not hurt to seek additional assistance here.

I have recently purchased a new RME Fireface UFX for my home studio.

It has been running smoothly, with no problems, on my older 27-inch Mid 2010 iMac.
The specs for this machine were as follows:
OS X 10.8.2
2.93 GHz Intel Core i7
4.0 GB DDR3 1333MHz
ATI Radeon HD 5750 1024 MB
1TB Hard Drive
On board mainboard & network drivers

As part of my home studio upgrade, I have purchased the new 27-inch Late 2012 iMac
The specs for the new machine are as follows:
OS X 10.8.2
3.4 GHz Intel Core i7
16 GB DDR3 1600MHz
NVIDIA GeForce GTZ 680MX 2048 MB
3.12 TB Hard Drive + Flash Storage (Fusion Drive)
On board mainboard & network drivers

I used Setup Assistant + Migration Assistant to transfer over all the files, and later on transferred some of the crucial files manually  (preference files, application support & library files) in order to preserve settings and preferences.

My issue now, is that after Totalmix is running consistently for a few minutes (usually about 10-15 minutes), the audio completely stops playing, it freezes, crashes, and refuses to reload. The Fireface USB Settings application refuses to reload as well.

The only way to remedy this issue seems to be with a restart, only to have the same problem happen again after 10-15 minutes of audio playback.

I have tried to manually uninstall (as per these instructions: http://www.rme-audio.de/forum/viewtopic.php?id=9233 ) and reinstall the drivers, as well as flashing the firmware on the UFX.
I have tried to repair the disk, as well as repair the permissions, through disk utility (even through system recovery mode).

Nothing seems to be helping to fix this issue.

Some more information on my setup:
I use the AES out signal to send a stereo channel which is daisy chained through a pair of Genelec 8250A's, with their own onboard DSP and volume control.
I have two headphones plugged in consistently, as well as one Mic input (48v off, of course) and one Instrument input.

If I let Totalmix try to load for 10+ minutes after it crashes, it loads up at a crawl and looks like this (screenshot below; perhaps this may somehow serve as a clue), but still does not function.

I hope that this is enough information for you to help me out with this issue.
If there is anything additional information that could help, I will be more than happy to provide it.

Thanks in advance for your help!