OK I ran it again using my iPhone as a timer this time!
1st run: 9.10 seconds
2nd run: 9:08 seconds
I believe the variable is due to reaction time hitting the stop button on the timer. Can't this test be rewritten to use Photoshop's built in timing function?
MacPro 6,1 3.5GHz 6-Core Intel E-5, 64GB 1866MHz DDR3 (OWC) RAM, dual AMD FirePro D500's, Apple 256GB PCI SSD.
Adobe Photoshop Version: 14.1.2 (14.1.2 20130923.r.427 2013/09/23:23:00:00) x64
Operating System: Mac OS 10.9.1
That's within a 10th of a second of what I got on the same setup (although I have a 32GB/1TB FWIW).