Multi display Hi-DPI scaling ???

[mon3]

I have three 4K displays connected to my Nvidia Quadro M2200 graphics card.
Two of them are 43" and one is 15".
I would like to use double (Hi-DPI) interface scaling on my 15" display and normal interface scaling on the two 43" displays.
Is this possible?

[xenopeek]

Unfortunately, no. HiDPI scaling is either on or off, and affects all connected displays.

It might become possible in the future, with Wayland, but right now I don't think there is a solution for this.

[mon3]

Thank you!
What do you think, Is this possible with any other linux distribution?

[xenopeek]

You will need to use Gnome and you will need to run it in a Wayland session. In general, that may give you a headache if you're into playing games as some graphics cards and/or drivers will be problematic on Wayland. Specifically the Nvidia proprietary driver (which you want for the best gaming performance) has very bad performance right now on Wayland. Some graphics cards (like my old Intel) will just not work with Wayland at all.

Wayland is the future but it has some ways to go yet... Programs that haven't been rewritten to support Wayland will be run in Xorg inside Wayland so some things that work with Wayland could possibly not work for such programs. I don't know (see above, I can't run Wayland ). Just giving you the heads-up.

I'd recommend using a distro that ships with Gnome by default and that uses the most recent release of Gnome (that is, release 3.26). While only supported for 9 months, Ubuntu 17.10 could be a good fit as you'll stay with Ubuntu (Linux Mint 18.x uses Ubuntu 16.04 as a package base). Ubuntu customizes the Gnome experience but optionally you can install gnome-session to get a pure Gnome experience on Ubuntu 17.10 as well (just switch to a Gnome session at the login screen after installing gnome-session). In April next year the next long-term support release of Ubuntu arrives (Ubuntu 18.04 LTS) so you'll have time to upgrade to that. That will be supported for 5 years.

On the login screen of Gnome use the gearwheel icon underneath the username box and make sure you have selected to run "Gnome" (meaning Wayland) and not "Gnome on Xorg". Gnome on Xorg can't do per display scaling, only with Wayland. Ubuntu calls it "Ubuntu" and "Ubuntu on Xorg". See screenshots and some other information about switching between Wayland and Xorg on Ubuntu 17.10 here: https://itsfoss.com/switch-xorg-wayland/

[mon3]

Thank You!

[JosephM]

Specifically the Nvidia proprietary driver (which you want for the best gaming performance) has very bad performance right now on Wayland.

This isn't exactly accurate. At least in most cases Wayland doesn't work at all with the Nvidia proprietary driver. There is supposedly some convoluted and complicated way floating around to get it working with Mutter/gnome-shell but I don't know if it even works and is probably outside of what most normal users would even want to attempt. Essentially at this point, Nvidia driver == no Wayland.