Windows 10: Multi monitor DPI scaling issue

Hi,

I've got a 4K monitor and a 1920x1200 monitor hooked up but the current "solution" for separate DPI scaling seems flawed.

If I set the 4K monitor as my main display and set it to 200% scaling with the 1920 display set to 100% what seems to happen is that windows also draws the 1920 at 200% internally and then scales it down resulting in a slight blur on everything.

If I set the 1920 display as the main display then the UI elements for the 4K screen are rendered at 100% but scaled up to 200% for display, so I effectively have a 4K screen behaving like a 1920 display - although there seems to be selective awareness that it's a 4K screen. Eg, Photoshop/Lightroom render the images at 4k resolution. Unfortunately desktop menus are also drawn at 4K but without the scaling, same for icons and file requesters and various other things.

Does anyone know if there's a way to get Windows to render each display at the correct scale rather than at same DPI as the main display?

:)

 

Mixed resolution scaling results in blurry applications?

Yes, you can turn all the DPI scales to 100%. Programs that you drag over to another DPI screen may appear to be a different size (in terms of how much space it uses on the screen when you measure with a real-world ruler), but they will not stretch/scale
and thus will always look crisp.

For background info on this, I have an article that may interest you:

DPI Scaling in HD Multi-Monitor Configurations

 

Windows Ink (Screen Sketch) of secondary monitor?

I think in MS they never used a multi monitor setup... otherwise I cannot explain the:

- SP4 dock issues and limitations

- Windows 10 inability to support multi monitor setup with different DPI (very common since nobody has a 4k external monitor while their SP4 has 200DPI scaling) without dpi scaling issues on everything, windows desktop included!

- Windows 10 ink inability to support 2 monitors

- Wrong pen cursor on a note app (example onenote) if the focus is on an other window (common if you have 2 monitor so you could have 2 foreground app windows)

ETC.

 

I can confirm this behavior with a UHD monitor and an HD monitor

 

I have been working with this issue for about a month now, and as near as I can determine, Win10 will set all of the displays to the same scaling factor. So using a 4K display with another monitor with a lower resolution, or using two different sized monitors, means that you will have to make some serious compromises. Some applications are also not playing well with the higher resolution displays.

My new Lenovo laptop has a 4K display and my second display is 24" HP running at 1920 x 1200. The HP looks gorgeous when running by itself, but when I run the 4K at 2048 x1152 and 100% scaling, the HP runs everything about 50% too large. Who knows why the HP looks so bad: it shows the same settings that it normally would run at. And at the same time, everything on the laptops's display is teeny! The laptop looks better at the 2048 x 1152 resolution with 125% scaling factor, but then the second display is horrible.

I have been unable to get most of my important programs to play well with the higher definition display. My drafting program would have dialog boxes that were truncated, with many choices not displayed, and Quickbooks would display icons at 1/16" tall. So setting the resolution down to about 50% of its native state seems like one of the better compromises.

Unless a 4K display is quite large, it will be necessary to run it a a high scaling factor. Otherwise most things will be too small to be legible.

 

NotSoFast, are you saying that you can't set the DPI scaling per monitor? That was added in Win10 but that's what introduced the issue I'm having. Windows 10 scales (and draws internally) all displays to match the scaling set for the main monitor and then scales the secondary monitor back to their individual setting for displaying the result.

 

Hi pxl8, I haven't been able to set the two of them independently. Whichever scaling factor is set last applies to both monitors. If you have found a way to set them differently, please let me know how to accomplish that. Because I've had no luck with it so far.
The resolution can be different, so you can have different dpi, but there is only one scaling factor for all displays. It appears to set them differently, but it doesn't.
Thanks,

 

It sounds like you've got stuck setting somewhere. To set individual scaling I right click on the desktop go to Display Settings and when the window opens click on the numbered monitor set the scaling, click on the next monitor and set the scaling again, then click apply.

 

I've done that dozens of times. At least on my Lenovo laptop, when you set the scaling for one display, the other display will assume the same scaling percentage.

 

I'm having the exact same problem as pxl8. I have several "HD" monitors an a single UHD monitors. I set scaling to 100% on the HD monitors and 150% on the UHD monitor. The UHD looks fine, but all the "scaling aware" applications look blurry on the HD monitors. Whenever I use an application on those HD monitors that isn't scaling aware, it looks perfect.

It seems pretty clear to me that Windows is actually scaling those other monitors to 150% then scaling back down to 100%, and the results are very poor. Anyone have any idea how to just disable scaling on a per-monitor basis?

 

Try rechecking the scaling factors. I think that all monitors will run at the last scaling factor selected. That has been my experience, where my primary monitor is UHD and secondary monitor is HD.

 

The HD monitors are obviously scaled to 100% - the size difference of the applications would be very noticeable if they were scaled to 150%.

 

I got a tech to respond in the Microsoft forums. After going back and forth with him a bit, it turns out a lot of applications use the primary display as their scaling baseline. They then re-scale according to the scaling percentage on whatever monitor they happen to be on. So if I made one of my HD monitors (which have scaling at 100%) the primary display, then Chrome would look fuzzy on my UHD display, which is using 150%. I tried it and sure enough, that's what happened. Basically it's exactly what pxl8 discovered, and the tech apparently indicates there isn't a viable solution apart from all applications switching to using vector graphics.

It's not a solution, but it's a better technical understanding of what's happening.

 

So what we have here is a failure for scaling to allow monitors to display properly if they have different dpi's. My 15.6" UHD monitor has a much larger dpi than my 27" HD monitor. Many applications don't perform well at scaling other than 100%. QuickBooks winds up with infinite field widths for some columns. So the best solution seems to be running at a lower resolution and scale at 100%. Even then, the second monitor doesn't look so hot.

 

I'm experiencing the same issue as pxl8 and Belisarius with my new Dell P2715Q (4K UHD) and a 1920x1200 display on the side. When I set the 4K display as my main monitor, everything in the side monitor becomes blurry, with the exception of File Explorer and Metro/Modern-style applications (so yeah, basically everything I want to use, even Microsoft Office 2016 suffers from this issue!), as well as old legacy software than wasn't designed with HiDPI displays on mind. And when I set the 1920x1200 display as my main monitor, then everything is blurry on the 4K one.

This thread is now about 4 months old, has anyone found a solution or workaround? I feel like I've tried everything, even setting some kind of downsampling on the NVIDIA Control Panel with a custom resolution (1.5*1200x1.5*1920 to make up for the 150% scaling factor) so I could use both displays at an effective 150% scaling, but that didn't seem to work either.

Any help would be appreciated,