As far as I can understand, the CPU and the hard disk throughput are not the limiting factors here ... the GPU is.

I've tried TW2 with my Mid 2011 iMac that has the same GPU but with half your VRAM and the results has been pretty depressing. Even at 1280x720.

Maybe the extra VRAM of your MBP could help a bit ... maybe.

I've read that under Windows 7 the 6770M is able to run the game at medium-high graphic settings and 20-30 FPS so there might be some hope if Apple updates the AMD drivers and VirtualProgramming devs do some optimizations to the game code.

(sorry for my rusty English)

I have a similar question. According to Mac Game Store, my video RAM is only 416 MB, and I need 512 MB to run Witcher 2. Further is says that my Intel HD Graphics 3000 isn't good enough, but lists Video (Intel) as not supported in the requirements anyway. Would it be possible to run the game anyway?

No, that card is way too weak. Sorry.

It's frustrating, since I only bought the computer a couple months before the game came out in the first place, you'd think they'd be using comparable hardware when they designed it. I have an Xbox, so it's not that big a deal, I just wanted the bonus features and the ability to import my saves (for whatever that's worth). Only just started playing the first one and thought that deal was too good to pass up.

Integrated cards are typically weak, though; it's not like that card was top-of-the-line when it came out. It's enough to play some older stuff and newer games with low graphic requirements (like Dishonored and Mass Effect 3), but we're talking about a game that would likely make a "top three most GPU-straining games in existence" list.

EDIT: It's worth mentioning that the game was (allegedly) playable with that card before the Enhanced Edition update, though only on the lowest settings and with a resolution of 800x600. I think the person who did that also used some background programs that helped, and even then they only got 20-24 FPS. Point is, it was technically possible back around the game's initial release. The Mac version is pre-patched to the Enhanced Edition, though, so that's not possible anymore. The EE made it more difficult to run, sadly.