If anyone needs to know what kind of speed that iRay for 3dsMax 2013 can perform at, here goes.
Instead of running a whole bunch of "theoretical" performance benchmarks, I decided to finally huff it and buy a GeForce GTX 760 - 2gb card and pit it against my Quadro's.
Short summary, it lost.
Long explanation, it won. Two insanely expensive Quadro K4000's (<cough> $700+ x 2) cards outperformed a $250 gaming card....but barely. (GTX 760) I don't consider that a win.
I think I need to rethink my stance on the power/reliability of the Quadro Nvidia cards vs. the run of the mill cheapo Nvidia cards.

Here's the renders:
They gradually improve as I
A) lengthen the timeframe (3 min, 5 min, 15 min, 45 min, 120 min) and
B) the GTX760 + Quadro 600 (then one at a time) and
C) number of cores (0-16)

3 min - 2 cards - 12 processors.jpg
5 min - 1 card760 - 12 processors.jpg
15 min - 1 card760 - 14 processors.jpg
45 min - 1 card760 - 14 processors.jpg
120 min - 2 cards - 16 processors.jpg

Pretty impressive for a $1050 rig (used Dell T5500 - 2 Quad Core Xeon 2.26Ghz - 12Gb Ram)
My thought process here is that it's better, faster, cheaper to run a GeForce GTX (4Gb +/-) card (for GPU rendering) and a low end Quadro 600, or K2000 - (2Gb) to run Revit. Mixed bag gets you the best of both worlds.