First off, thanks much for all the helpful info on these boards. I've searched for this topic and have not found a clear answer, so please point me to the right thread if I've just missed it.
OS 10.8.3 enabled driver support for many PC graphics cards to be used in the Mac Pro, the only drawbacks being lack of a boot screen and, in some cases, that the cards only run at PCIe 1.0 speeds (2.5GT/s) rather than PCIe 2.0 speeds (5.0GT/s).
(As I understand from research so far, seems like Mac Pro 3,1 runs PC GPUs at 2.5GT/s and 4,1 & 5,1 runs them at the full 5.0GT/s).
I'm looking for advice on this topic when comparing these two graphics cards:
GTX 680 Mac Edition with 2GB VRAM
GTX 680 PC (EVGA or ASUS) 4GB VRAM
Reading Peter Chamberlain's recommendations on other posts it seems 4GB VRAM will soon be the recommended VRAM amount in the Resolve configuration guide.
My question is: will the PCIe 1.0 speeds imposed by a PC version of the GTX680 4GB be worth the 4GB VRAM, or is this just silly when there is a perfectly good Mac Edition available that will run at PCIe 2.0.
(No interest in flashing the rom and am totally OK with forgoing the boot screen. This is more of a theoretical quandary than a please-help-me with-my-specific-setup question.)
Hopefully this info is useful for other folks considering a GPU upgrade for their lowly non-Cubix grading rigs.