Props to the author for putting in what looks like ton of work trying to navigate this issue, shame they have to go to these lengths to even have their case considered.
New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays
51–60 of 180 posts
Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays
#52If the theory about framebuffer pre-allocation strategy is to hold any water, I would think that 5k and 6k devices would suffer too, maybe even more. Given that you can attach 2x 5k monitors, the pre-allocation strategy as described would need to account for that.
Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays
#53How did none of the Apple devs notice this? 4k 32" inch is the industry standard for HiDPI monitors.
Not in the Apple world, and this article is centered on Apple. https://bjango.com/articles/macexternaldisplays/ - 24" you need 4k - 27" you need 5K. - 32" you need 6k. Windows subpixel aliasing (Clear Type) manages a lot better with lower pixel density. Since Windows still has a commanding market share in enterprise, you might be right about the industry standard for HiDPI but for Apple-specific usage, not really.
Meanwhile, Apple had this but dropped it in 2018, allegedly under the assumption of "hiDPI everywhere" Retina or Retina-like displays. Which would be great...except "everywhere" turned out to be "very specific monitors support specific resolutions".
Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays
#54This is not a normal retina configuration. This is a highly unusual configuration where the framebuffer is much larger than the screen resolution and gets scaled down. Obviously it sucks if it used to work and now it doesn't but almost no one wants this which probably explains why Apple doesn't care.
Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays
#55This is not a normal retina configuration. This is a highly unusual configuration where the framebuffer is much larger than the screen resolution and gets scaled down. Obviously it sucks if it used to work and now it doesn't but almost no one wants this which probably explains why Apple doesn't care.
It's also why when you put your Mac into "More Space" resolution on the built-in or first-party displays, it tells you this could hurt performance because thats exactly what the OS is going to do to give you more space without making text unreadable aliased fuzz, it renders the "apparent" resolution pixel doubled, and scales it down which provides a modicum of sub-pixel anti-aliasing's effect. Apple removed subpixel antialiasing a while back and this is the norm now.
I have a 4K portable display (stupid high density but still not quite "retina" 218) on a monitor arm I run at, as you suggest, 1080p at 2x. Looks ok but everything is still a bit small. If you have a 4K display and want to use all 4K, you have the crappy choice between making everything look terrible, or wasting GPU cycles and memory on rendering an 8K framebuffer and scaling it down to 4K.
I'm actually dealing with this right now on my TV (1080p which is where I'm writing this comment from). My normal Linux/Windows gaming PC that I have hooked up in my living room is DRAM-free pending an RMA, so I'm on a Mac Mini that won't let me independently scale text size and everything else like Windows and KDE let me do. I have to run it at 1600x900 and even then I have to scale every website I go to to make it readable. Text scaling is frankly fucked on macOS unless you are using the Mac as Tim Cook intended: using the built-in display or one of Apple's overpriced externals, sitting with the display at a "retina appropriate" distance for 218ppi to work.
Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays
#56TFA doesn't say -- does anyone know if this applies to 5k and 6k monitors? On my 5k display on a M4 Max, I see the default resolution in system settings is 2560x1440. Which is what I'd expect. If the theory about framebuffer pre-allocation strategy is to hold any water, I would think that 5k and 6k devices would suffer too, maybe even more. Given that you can attach 2x 5k monitors, the pre-allocation strategy as desc…
Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays
#57This would be even more compelling if you included screenshots with magnified detail insets showing the text blur.
Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays
#58Earlier quoted context omitted.
No, it didn’t get fully fixed. Fucking with DP 1.4 was how they managed to drive the ProDisplay XDR. If your monitor could downgrade to DP 1.2 you got better refresh rates than 1.4 (mine could do 95Hz SDR, 60Hz HDR, but if my monitor said it could only do 1.2, that went to 120/95 on Big Sur and above, when they could do 144Hz HDR with Catalina). I would be absolutely unsurprised if their fix was to lie to the monitor…
Ahh, true, I now have 120Hz top, but it's fine, why I said fixed :) I now recall in Catalina I had full 144Hz and VRR options! Monitor is Dell G3223Q via Caldigit TS4 DP.
People at the time were trying to figure out the math of "How did Apple manage to make 6K HDR work over that bandwidth?" and the answer was simply "by completely fucking the DP 1.4 DSC spec" (it was broken in Big Sur, which was released at the same time). The ProDisplay XDR worked great (for added irony, I ended up with one about a year later), but at the cost of Apple saying "we don't care how much money you've spent on your display hardware if you didn't spend it with us" (which tracks perfectly with, I think, Craig Federighi spending so much time and effort shooting down iMessage on Android and RCS for a long time saying, quote, "It would remove obstacles towards iPhone families being able to give their kids Android phones").
Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays
#59Is this for specific verisons of macOS? The article doesn't mention it.