A couple of thoughts, that may not sit well. If you are looking to run (6) 1080p discrete/unique video surfaces. There is no amount of external GPU that you can hook into a laptop that has enough bandwidth to support the GPU's for that many displays.
The reason we use towers (like your older
MAC pro, which is a
bit long in the tooth admittedly) is for the High-speed data connections direct between the CPU and the GPU (PCIe x16) Modern USB 3.1 Gen2, Lighting bandwith is quite impressive but you would need probably 3 of those ports on your 2016 laptop to get the quality/speed/
latency that you would't hate (and even then if all those ports are connected together on the motherboard they are all sharing the same data bus.
If you are all on board with
Qlab. It's time for a new
Mac pro. I don't quite know where you are gettin $8-10k MacPro costs from. But if you really want to handled 6 discrete outputs you are venturing into major video hardware that operates outside of your desktop systems and to very niche and expensive market.
My
Venue bought a MacPro (trashcan style) fairly baseline for $4000* (*we purchased 2 HD
LED monitors better then budget
level stuff,
Mouse Keyboard, Active 1-channel
DVI splitter and various other insundry adapters. All told maybe an additioanl 600$). It's runs 2 video monitors on the
desk at 1920x1080 (Our main
projector is a Mirror of Display 2, And I've run 2 additional outputs at 1280x720 for the odd one of show. It handles it just fine provided the media has been optimized for
Qlab and encoded properly.
I believe the limits of the MacPro's are still (4) unique displays. To go beyond that you need to fiddle with the Matrox triple/doublehead to go hardware (i'm not knowledgeable about how they actually accomplish what they do); or you need to investigate in depth the outboard PCIe x16 Bay's and Rack chassis that are sudo-supported by Apple and install additional Graphics Cards. (which is what I think you are thinking.) The later (an external PCIe x16 box) will likely not work with a laptop because the bandwidth limitations inherent in the design of laptop computers.
Other thoughts:
You got nearly 10 Years out of your first
Mac Pro, Thats great value for money. Is an investment in a computer you'll keep for 5-7+ a bad decision even if it costs $5k upfront? Your IT department is probably swapping out every computer in the district every 2-3 years. Our College IT Department was happy to
purchase our MacPro with the prospect of holding on to it for 5yrs or more, your IT department may feel similarly. Because generally speaking when you
purchase a poweruser kind of machine our workload that we put it through doesn't change much in the theater world. The next big step will be 4k resolutions as standard but thats' still probably 5 years away, and you'll find that to move actual display technology to those resolutions will cost 10's of thousands of dollars, and happen 10 years after that for institutions.
Summary:
I also dislike the idea of using my personal computers for this kind of work. It's just a liabilty I don't wan to have or put on others. What happens when somebody spills coffee all over it.
I still think the EGPU's while a great way to get single source/display
power on a mobile
platform (and USB3, and Lightining is blisteringly fast, I don't think even though the cards may have 3 or more outputs, that you can use all of them simultaneously. That may have changed in the last couple of years but the Last Performance GPU I purchased for my Win PC was limited to only using 3 of the 4. That said, As I was just typing that, you'd probably still have 1-2 video out on the laptop itself still.
I think a New
Mac Pro should be what you strive for, and
settle on your above EGPU as a last resort. (Or if wand when yo require more then 4 unique/discrete outputs.
If you have any questions i'm pretty computer tech Savvy but I also don't keep on the bleeding
edge of technology either, and the eGPU's are both groundbreaking as technology and quite promising with the speeds that external connections can now manage. (eGPU's before Thunderbolt2/USB3.1 Gen 2 would have been unheard of
)
