Game won't launch on Threadripper/Vega

[flicman]

I have a rather unique setup, but no other game in my Steam library is having trouble, so it's clearly something with ACO. I'm running the Threadripper 1950, and yes, I've disabled all the cores. I've tried 16 threads rather than 32. I've tried 8. I *tried* to try zero, just to see if no processor at all would run the game, but taking the CPU out of the system causes boot problems, so I can't even get to Windows to load Steam to load Ubisoft to load the game.

Anyway, the splash screen loads and *usually* another, blank screen loads behind it, but even if I select the game screen, it brings up a 1080p window that shows my desktop through any other windows open and then just sits there. if I click on something else, it auto-minimizes and that's it. I left the game open overnight the other day just to see if it would eventually load, and, predictably, it didn't. Steam shows that I have 11 hours of gameplay, but it's all been loading screen.

My setup is Threadripper/Vega64/4k monitor as my main, with 2 1080 monitors on either side. There is also a RX560 running 3 1080 screens above that. I haven't tried taking out the 560 and running just the three monitors, nor have I tried disabling everything but my main monitor because that's not a solution that I'm willing to accept. Mostly, I'm just posting because nobody else seems to be having this issue, but maybe nobody is running the same weird-ass system as I am, either. I've got the latest drivers for my video card (and everything else - this system isn't even 2 weeks old and I've been careful to download the updated-est crap that each vendor has to offer), and everything is working as expected. Benchmarks are good, video rendering is fast as hell and *every other game* works great.

Anyone have any novel ideas for a novel system?