Some GPU Questions

[knouroozi]

Got a couple questions for the experienced people here, so I'll get to the point.

 

Question #1: Dual GPUs in OS X

I know that Crossfire/SLI don't work, but what if I want a cheap, standalone GPU (i.e. GT210 or HD5450) to drive the display but a more powerful one (i.e. 6870 or GTX 560) to do the computing? Is this possible? Would I have to use the Mac Pro 3,1 SMBIOS for proper power management?

 

Question #2: FCPX vs. Adobe CS6

I do my fair share of video editing, so performance here is important to me.

FCPX has OpenCL GPU acceleration (which works with either AMD or nVidia GPUs), which is an open standard but slower than nVidia's CUDA, something that Adobe CS6 supports very well through the Mercury Playback Engine. I've heard that removing a certain file allows the Mercury Playback Engine to work with non-CUDA GPUs, and I assume there will be some performance loss because of the lack of CUDA cores on AMD GPUs. I'm definitely biased towards AMD GPUs, because of their native support for OS X (but that'll change with the nVidia 6XX series come Mountain Lion), so what should I do here? Stick with AMD and FCPX, or go nVidia 5XX + drivers and CS6, or wait for Kepler and have a vanilla 6XX + CS6? Out of curiosity, how would AMD + CS6 work out?

 

Question #3: SpeedStep and Power Management

It seems fairly certain that the upcoming high-end 27" iMac will use a low-voltage i7-3770S or an i7-3770, which guarantees anyone with those CPUs SpeedStep as long as they set up their SMBIOS properly (something that I've achieved this same outcome with my current i5-750 and an iMac 11,1 SMBIOS). After the new iMacs get released, I get the exact same CPU (be it S or no S). Is there a specific graphics card I need to get proper power management?

 

Answers for this last one can be theoretical, like "the desktop version of GPU", meaning that if the new iMacs get a GTX 660M then I am to get a GT 650 (assuming nVidia continues with its current naming scheme).

 

If I have made a mistake, please tell me, as I would be more than glad to know.