Windows 10: What is up with my monitor's dpi?

Alright, So the screen looked a bit weird, Then i noticed the app icons were small and stuff. Then i noticed stuff being a little too small for my liking, What is up with the DPI? It's annoying me. I bought a new monitor today.

:)

 

Dual monitors with different DPI settings do not give correct scaling

An issue with DPI scaling arises when using two different scaling factors. The screen with the lower DPI display is fuzzy/blurred (most easily seen in text).

Hardware and settings

These are the hardware and settings involved:

• 1x primary 3840x2160 27" monitor with DPI scaling set to 150% (because regular text is unreadable at 27").
• 1x secondary 1920x1080 24" monitor with DPI scaling set to 100%, displaying blurry text and images at these settings.

Workarounds

When I use the same DPI scaling on both monitors the display shows correctly. This gives two undesirable workarounds:

• Setting 100% DPI scale on the UHD screen fixes display, but makes text unreadably small on this monitor.
• Setting 150% DPI scale on the HD screen fixes display, but makes text so large I barely have any screen space left on this monitor.

Is there per chance a better solution to this problem? Is this a Windows bug or am I using DPI scaling in the wrong way?

EDIT: Here's the system info from dxdiag just in case.

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System Information

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Time of this report: 11/14/2015, 13:09:59

Machine name: -

Operating System: Windows 10 Pro 64-bit (10.0, Build 10240) (10240.th1_st1.151104-1714)

Language: Dutch (Regional Setting: Dutch)

System Manufacturer: To Be Filled By O.E.M.

System Model: To Be Filled By O.E.M.

BIOS: BIOS Date: 07/09/14 21:30:44 Ver: 04.06.05

Processor: Intel(R) Core(TM) i7-4770K CPU @ 3.50GHz (8 CPUs), ~3.5GHz

Memory: 8192MB RAM

Available OS Memory: 8112MB RAM

Page File: 5936MB used, 3454MB available

Windows Dir: C:\WINDOWS

DirectX Version: 12

DX Setup Parameters: Not found

User DPI Setting: Using System DPI

System DPI Setting: 144 DPI (150 percent)

DWM DPI Scaling: Enabled

Miracast: Available, with HDCP

Microsoft Graphics Hybrid: Not Supported

DxDiag Version: 10.00.10240.16384 64bit Unicode

 

Resolution & DPI scaling on 32inch monitor

Samsung LC32F397FWNXZA 32"
resolution 1920 x 1080

graphics card:

GeForce GTX 1050 (2GB)

Maximum Digital Resolution 7680x4320@60Hz2

Would this suggest that it is the monitor that is the limiting factor?

I'd like to just make the apps smaller but unable to scale below 100% or adjust the DPI below the default.

 

Blurry text on secondary monitor in multi-resolution, multi-DPI setup


This is probably the most painful issue I have with Windows 10 right now (and likely previous versions as well, but I didn't have a multi-monitor setup back then).

The monitors I have are as follows:

1. 3840x2160 (4K UHD) monitor with preferred DPI: 144 (150%)
2. 1920x1080 (Full HD) monitor with preferred DPI: 96 (100%)

Whenever one of these monitors are set as primary, all desktop applications displayed on the secondary monitor (doesn't matter which) has blurry text. Exceptions are the Windows Store Apps like Windows Store and Microsoft Edge, along with the Taskbar/Start Menu, the Taskbar/Start Menu settings screen, the Taskbar context menu, and the desktop context menu which passes the DPI test with flying colours, with crispy text on both monitors (occasionally a DPI switch bug gets in, but I can mostly ignore that). The problem is, as you can probably guess, is that >99% of the applications I use aren't Windows Store Apps.

Here are some screenshots. The "Taskbar and Start Menu Properties" text is what the text should look like while the Visual Studio 2015 text is an example of the text most desktop apps get. The blurry image is what happens when the UHD monitor is not the primary monitor.
Attachment 48493Attachment 48494
Note: Both of these screenshots came from the 150% DPI monitor so it's best viewed at that (144) DPI level. The 96 DPI monitor is similarly affected.

Things I've already tried:

• Reinstall the graphics driver (this was unhelpfully given by a Microsoft Support Engineer). Did this multiple times in fact for unrelated reasons.
• Reinstall Windows 10 (through Reset This PC recovery option). I did this for also unrelated reasons but it definitely doesn't fix this issue.
• Use the XP Explorer "fix". Merely worsens the problem.
• Adjusting ClearType options. Alleviates the issue a bit but see next point.
• Disabling ClearType on the affected monitor. The text obviously sharpens, but it's painful to read and a close inspection of the text reveals the issue isn't solved at all, only mitigated slightly.
• Replacing the video card. I swapped this in with my older GTX 560 Ti but it's obvious the problem remains. Both it and my current card are NVIDIAs though, so it's vaguely possible the drivers or the cards themselves are the cause. I don't have an ATI/AMD card (that still works, at least) to test the setup and every Intel iGPU I have either has only one monitor output or is incapable of handling UHD resolutions.

Things I won't try:

• Setting both monitors' DPI to 96. Text would become microscopic considering the UHD monitor's actual size.
• Use the text resizing feature instead. I'm going take a wild guess that this is not monitor-specific and would cause everything on the HD monitor to be far too large to the point that I'd rather unplug it.

Does anyone have a multi-resolution, multi-DPI, multi-monitor setup with or without this issue? The text is painful to read on whichever is the secondary monitor right now, and is extremely apparent whenever the background is dark.