2013 Mac Pro: Sigma Photo Pro X3F Raw to 16-bit TIF
A big thanks to Other World Computing for loaning the 8-core 3.3 GHz Mac Pro and authorized Apple dealer B&H Photo for loaning the 6-core 3.5 GHz Mac Pro.
Version 5.5.3 of Sigma Photo Pro is a 32-bit program, and runs like molasses on all machines, taking 7.9 seconds per file on the fastest Mac Pro.