Scaled resolutions lag

[VroepVroep]

Hi,

I recently got myself a 4k monitor, it looks absolutely gorgeous and the Mac OS scaling works very well-

-until you start scrolling and panning in applications.

You see, when I have it running at 4k resolution with no scaling (so everything is tiny) everything works like a charm, very smooth. Applications like Logic Pro and Sibelius work without a hassle.

However, when I enable scaling/high DPI mode it becomes unusable. Scrolling and panning drops down to about 2 fps, which practically makes it impossible to use. I'm someone who tries to understand things, but I can't really figure this one out. Since in scaled mode it's still pushing the same amount of pixels as in non-scaled mode I'm kind of spooked about what is happening here.

So, now I am stuck with everything being tiny since it's the only way I can properly use my computer. Does anyone know what I can do about this?

I'm rocking a GTX 770 2GB with a 4K monitor and a second 1080p monitor. In Windows this exact setup works perfect, with all applications (except of course for Windows' terrible DPI scaling).

Any help is appreciated!

 

[Fl0r!an]

However, when I enable scaling/high DPI mode it becomes unusable. Scrolling and panning drops down to about 2 fps, which practically makes it impossible to use. I'm someone who tries to understand things, but I can't really figure this one out. Since in scaled mode it's still pushing the same amount of pixels as in non-scaled mode I'm kind of spooked about what is happening here.

Actually it doesn't necessarily. If you choose "3200x1800 HiDPI", OS X will render everything internally at 6400x3600 and downscale it to 4K/UHD afterwards. That's very inefficient, but that's how HiDPI works in OS X, since it lacks proper vector scaling.
Only in case of "1920x1080 HiDPI" the number of pixels will equal native UHD.
However, the performance drawback shouldn't be that bad. I'd try to install the WebDrivers and see if they improve things.

 

[VroepVroep]

Actually it doesn't necessarily. If you choose "3200x1800 HiDPI", OS X will render everything internally at 6400x3600 and downscale it to 4K/UHD afterwards. That's very inefficient, but that's how HiDPI works in OS X, since it lacks proper vector scaling.
Only in case of "1920x1080 HiDPI" the number of pixels will equal native UHD.
However, the performance drawback shouldn't be that bad. I'd try to install the WebDrivers and see if they improve things.

Thank you for your reply!
Wow, that seems highly inefficient indeed. However, a card like the GTX 770 shouldn't even have the slightest issue with that anyway.
I'm sorry, I should've mentioned that I already am on the latest Nvidia Webdrivers.

 

[VroepVroep]

This just got even weirder:

I installed SwitchResX and pushed the 6400x3600 resolution to my monitor (looks awful of course, but for the sake of the experiment) and the whole UI was perfectly smooth, and all my applications ran smooth as butter!

Since the 3200x1800 resolution is simply a scaled 6400x3600 resolution how is it possible that the 3200x1800 resolution completely kills the UI smoothness and makes my heavier applications unusable in terms of performance?

 

[lipfroy]

I'm suffering with same issues on High Sierra. Did you figure out the workaroud?