iMac Pro compatibility

The iMac Pro supports Displayport 1.2 . The XDR requires Displayport 1.4 ( different chipset ). So no, it won't work without an eGPU in between to bridge between 1.2 and 1.4. So now have a situation where your iMac Pro Vega 64 display adapter doesn't support the XDR but the $1200 eGPU with the Vega 56 and half the memory does. I have a pair of loaded iMac Pros. Now faced with a kludge - installing the unloved eGPUs just to get the XDR to work or unloading the iMac Pros to get new Mac Pros breaking the budget. The iMac Pro now seems to be orphaned - at least on the display side. It would be nice if Apple offered a discounted bundle of the eGPU Pro and XDR to iMac Pro owners.

Talked with local Genius Bar staff and Apple tech support and received inconclusive and sometimes conflicting answers regarding the viability of the eGPU Pro with an iMac Pro. Question is could the internal iMac GPU support the built in display while the eGPU supports only the external display. If so, is the selection of Thunderbolt Bus relevant? Absent a definitive answer from Apple staff I starting digging around in the developer.apple.com and found this article which seems directly on point. https://developer.apple.com/documentation/metal/gpu_selection_in_macos/understanding_multi-gpu_and_multi-display_setups . From the article one could infer that an external GPU can be confined to it's own display. Asked Apple to confirm the article is timely and accurate.

https://www.macrumors.com/2019/12/13/pro-display-xdr-imac-pro-5k-resolution/