why not just configure Windows to mirror the displays? That seems a lot cheaper and more flexible than pass through. And you wouldn't need to worry about matching resolutions and refresh rates
In that case I’d need a 1080 physical display on the machine mirrored to the KVM. For the type of stuff I’m doing that’s a bad use of monitor / desk real estate.
Same complaint. The 1080p cap when mirroring is annoying and when it acts like a third screen it becomes a real nuisance.
Would a HDMI dummy plug work?
Then you can’t see what you’re doing. It’ll run with the HDMI unplugged but at that point you’re undoing a core reason for using it to begin with.
I think I misunderstood the original problem
it doesn't seem like Windows makes it easy, but it's not really required that mirror'd displays must have the same resolution. Sure can throw fancier and more powerful hardware at it, but this is something software could rather easily do