In all fairness I'm honestly surprised it performed as well as it it on the Hackintosh VS Win 7 on the same hardware. Given the fact that Apple has almost the entire deck of cards stacked against them on this particular concept, at this time any way. Any one who follows the performance of graphics cards realizes how much of a difference drivers can make. Apple nor valve has had any real reason to optimize any of the drivers / OpenGL libraries for games, as this is not what a Mac usually does. Being that the hardware is the same, it comes down to software at this point. So it'll be interesting to see if Apple will lay some dev time down on this to usher in the Mac as a gaming platform, or if they will ignore it for not being their target markets cup of tea. All things the way they are, I'd classify the Portal test as something closer to "Prototype" or "BETA1" at best -- And make no judgments on the Mac's ability to be a viable gaming platform at this point in time.
As to the hackintosh driver variable, for the card mentioned above, Apple does release a Mac with that exact card. The GPU on the Mac version of that same card, is the same as the PC version. (Infact its usually the same card save the required software changes to make it work with Apple's EFI) -- The community contribution is a a mod that will either
A> Tell OSX to load the driver for THIS card via "tricking it"
or
B> Mod the driver its self to include the device ID of the card in question. In any case, you're getting the driver Apple uses on the card with no functional differences to it.
I'm also impresses TH decided to benchmark the hackintosh, I didnt expect that. Nice!