AKiTio Thunder3 DP question
I've been rethinking my approach on my compact eGPU. Which is never gonna happen. Now I started to look for alternatives.
I am down to 780 and 980. I've noticed that the TB3 enclosure has a DP by itself. If I attach a monitor there will that be powered through the eGPU or its a mere extension of the TB port from the MBP? In the latter case would be possible if I run an iGPU to be actually powered by the eGPU through the motherboard of the MBP? The video signal going something like:
- MBP -(TB3)-> eGPU -(TB3)-> MBP -(TB3)-> AKiTiO -(DP)-> Monitor
- MBP -(TB3)-> eGPU -(PCIe)-> AKiTiO DP port -(DP)-> Monitor
late-2016 13" Macbook Pro + [email protected] (TB3 to TB2 adapter) (AKiTiO Thunder2) + macOS 10.12.3
late-2016 13" MBP + Quadro M2000/FirePro WX5100/GTX750-TB3 (AKiTiO Thunder3) + macOS 10.12.3
(Custom Thunder cables)
Yes, attaching the LCD to the eGPU enclosure’s DP port will see it being driven by the iGPU. To have that LCD accelerated by the eGPU require NVidia Optimus/AMD X-Connect (Windows) or the fake LCD method (macOS/Windows) explained here.
It means your TB3 eGPU link will now be carrying additional LCD display traffic overhead, which at [email protected] will max out at ~15Gbps. That would be an OK workaround to your LCD’s DP 1.2 spec which you want to run at 60Hz alongside another 4K LCD driven by the eGPU.
DP TB3 traffic also uses an alternate pathway to the CPU so can get 40Gbps of PCIe+DP traffic on your TB3 link. Can somewhat see this in the pic below:
Do note that using the eGPU to drive a monitor this way will result in similar performance to an internal rather than external display. While there's extra bandwidth available for the DP link from the iGPU to the DP output, frames must still be copied across the PCIe bus from the dGPU to the iGPU.
Do note that using the eGPU to drive a monitor this way will result in similar performance to an internal rather than external display. While there’s extra bandwidth available for the DP link from the iGPU to the DP output, frames must still be copied across the PCIe bus from the dGPU to the iGPU.
Yes, having a DP LCD attached to the Thunder3 will see the host have incoming eGPU traffic (DATA-PCIe) for what needs to be displayed, which is then sent as outgoing LCD traffic (DISPLAY-DP) managed by NVidia Optimus or AMD X-Connect. Pic below from Intel reference: