And another question, how to you think they will do that?
How they will implement Thunderbolt on the Mac Pro?
They will most likely do it the same way they do it on
all of the rest of the Macs. They will embedded a GPU on the motherboard.
That design involves no cables for the user to hook up or not. Cleaner internal presentation. Allows Apple to share component costs between Mac Pros and other Macs (probably the iMac). It does not involve customer/proprietary PCI-e graphics cards.
That cable should go to Graphics card, but Graphics card is unable to provide Thunderbolt speeds...
The TB Display cable to the Mac Pro's graphics card?
No, that won't work. While Thunderbolt is backward compatible with Display Port ( you can plug a Display Port device into a TB device), Display Port is not forward compatible with Thunderbolt. You can't plug a Thunderbolt device into a Display Port Computer/GPU. In short, plugging in a Display Port device only works at the "far" end of the chain (away from the TB computer).
Graphics cards are quite capable of Thuderbolt like speeds. They just don't provide encoded PCI-e data. Only video data.
If talking about a future design of the Mac Pro where the Thunderbolt is a port on the Graphics card, this approach is highly unlikely. It gets pushed forward as a "possible" option by those who primarily want Thunderbolt to show up on a PCI-e card so they might somehow "retrofit" TB onto older computers. That isn't going to happen.
Thunderbolt requires that the whole motherboard was designed for Thunderbolt. The Thunberbolt controller takes
three inputs (x4 PCI-e , 1-2 DisplayPort signals , and the TB switch control) , so putting the controller on a GPU card is very much non standard. Even is steal PCI-e bandwidth from the card's connection you still don't have the TB control signals.
There is a possible variant where a Display Port signal is routed off the card and onto the motherboard. Right now that would mean a custom card. Second it likely would involve an internal cable(s) that needed to be connected. [ need two if connecting two Display ports outputs from GPU]
It is a more complicated and more expensive ( additional video switching , assembly , etc. ) solution. I don't think Apple or the mainstream PC vendors are going down that path in the next year or so. When Thunderbolt ships standard on over 50% of all desktop personal computers ... maybe. But not now or 2013.