I have a brand new Macbook Pro*, running a fully up to date copy of Audition (2014.2 release). I'd just finished putting together a 90-minute podcast**, and was a little disappointed when Audition estimated the mixdown would take around 7 and a half hours. I gave it half an hour before giving up.
After some googling, I thought I'd try exporting it through a trial of Audition CS5.5. It finished the mixdown in 6 minutes flat.
If anyone can tell me what on Earth is going on here, I would very much appreciate it.
* Mid-2014 15-inch, 2.5 GHz Intel Core i7, 16GB RAM. Running Yosemite 10.10.1
**6 audio tracks, 5 running through a bus. Dynamics Processors running on each track, and a Parametric Equaliser & DP running on the bus. Hard Limiter on master track.