Mirrored dual monitor setup for 144hz and 60hz.

[Calabrel]

I have a GTX 1070 and i5 6600K. I want to upgrade my primary monitor to a 144hz monitor, but my setup has a mirrored monitor across the room, this monitor would still only be 60hz. I have a third, extended, display that's 60hz as well, but I've read about a dozen threads here that say that's no problem.

Two issues I'm worried about because the displays are mirrored:

Will there be tearing and/or other issues on the 60hz display?
Will the 60hz display limit the 144hz display?

I guess another question I would ask, in general, is how does the GPU process a mirrored display like this? Does gaming at 3840x1080 extended put the same processing strain as mirroring two 1920x1080 displays?

Edit: To clarify, each monitor has its own input to the video card, there are no splitters or adapters.

 

[LilDog1291]

I'm honestly not sure on this one but here is how I imagine it works but I'm sure someone here can confirm or deny it for me. The video card would render the image to be displayed. What you see at each time interval is determined on how many times your display requests a frame from the GPU. A monitor can request a frame at its own discretion without having to trouble the GPU about any type of synchronization in signal. So the GPU is just constantly delivering a video stream and your monitors are deciding how many frames per second you will see.

If you notice, there are no refresh rate limits on graphics cards, only on the displays themselves. So technically you could have a monitor with a 144Hz refresh rate or one with a 600Hz refresh rate like the old plasma TVs and it would not matter to the GPU. It only matters to the displays. Of course this doesnt translate into gaming experiences since video game FPS is often synced in some fashion to your monitor's refresh rate. I imagine that as long as Vsync isn't enabled you shouldnt have any weird FPS limits. Otherwise I think it would pick the lowest common denominator to sync to.

Again not sure on this, just speaking from what knowledge I do have. Hopefully someone here has tried it in the real world.

 

[Calabrel]

That thinking does make sense, but has anyone tested this or any input, don't want to buy the new monitor unless it will work with my setup.