AMD 7950 and Saphire 7950 Mac Edition. Difference?

I'm considering boosting the graphics performance of my MacPro (5,1).

I'll either grab a dirt cheap GT120 to drive the second monitor (1080 HD) so the 5870 I already have can drive my main monitor (2560x1440 WQHD) and Photoshop, or I'll get a AMD 7950 as the sole graphics card.

Since the Saphire Mac Edition of the 7950 isn't obviously that popular, its price remains quite high. The standard 7950 costs £100 less.

What, exactly, is the difference between the two cards? If its just the onboard ROM that initialises with the EFI so you can see the boot menu then I'll just spring for the standard 7950 and keep the 5870 as a spare.

-Cheers!