The one thing about the new Mac Pro’s was how they would handle Thunderbolt and Displays. With the laptop based Mac’s such as the Mac Pro and iMac’s it was simple you just added the graphics output and the Thunderbolt output into the same interface. What about discrete graphics cards in the Mac Pro though? PCI Express 2.0/2.1 basically had a 16x rate of 16000 Gbps and if you took 10000 Gbps away it did not help anywhere in the graphics department. What I did not know a few weeks ago was that in 4Q 2010, PCI Express 3.0 was finalized and doubles the bandwidth and at the same time reduces overhead from 20% of PCIe 2.0 to 1.5% for PCIe 3.0. So the technical barrier to having Thunderbolt on a PCIe graphics card appears to be gone. It’s also a huge boon for gamers who do SLI in which you use several graphics cards to generate a superior graphics experience at higher resolutions than a single card could handle. The days of limited bandwidth on the 3rd and 4th cards are numbered.
It also means that in theory the Mac Pro can have more than 1 thunderbolt port without graphics degradation since Mac Pros do not have SLI available to them, it leaves open a lot of bandwidth to be used towards Thunderbolt. We’ll see in a few weeks when they come out.