Multiple screens of different dpi show blurry text (really bad)

[Roy B1]

my setup:
win10 with 3 monitors: 4k 27" monitor and two 24" 1920x1080 monitors.
windows suggested 150% dpi for the 4k and 100% for the others.
4k looks great but the 24" (with 100% dpi!) looks terrible. The text is all blurry.
I saw many similar issues (sorry, can't post links yet)
and tried the registry changes, but all fixes (including the utility that is out there) set all monitors to the same DPI.
I can't do 100% in the 4k, it's too small, and I must do 100% in the small screens, otherwise it's too big.
Got latest drivers for my GeForce GTX 970 and monitors (vendors drivers for all monitors).

I really don't want to let go of my 4k, but it is impossible to use the other ones.
I attached an example for when the 4k is d/c (top) and when it is connected (bottom) from the 24" monitor. it is not really text but is shows how terrible it is, I simply can't read for more than a few minutes.



Please help.
thanks,
Roy.

 

[Roy B1]

Interesting update,
The monitor I set to be the main monitor is always totally clear. when I set my 24" to be the main, the 27" was blurry.
It's a shame having a blurry 4k monitor.
why is that?
any ideas what I can try next?

 

[astondg]

Have you tried to sign out and back in after connecting and configuring the monitors & scaling settings.

EDIT: Just to clarify, the suggestion above is due to Windows only setting up certain aspects of scaling on log in. One issue that is highly apparent with my Surface is if I sign in to my Surface standalone and then plug in an external monitor of a different DPI the external monitor is very slightly blurry until I log out and back in. OR if I sign in to my Surface while plugged in to an external monitor and then unplug the external monitor the display on the Surface is blurry, again until I log out and back in.