Apple doesn't even do 200% scaling on most of their laptops by default. My 2018 15" MBP has a native resolution of 2280x1800 but the default is looks like 1680x1050 not looks like 1440x900.

Do you have difficulty viewing 1080p at 15" at 100% scaling? I found that very viewable on my old laptop so 4K at 200% should be fine. You can adjust the scaling if you're really bothered by fractional scaling. It's improved a lot too. Much better than it was in the Win 8 days.

It depends on the version of MacOS installed, it used to be the integer 2.0x scaling in the "best for display" default.

They moved to a fractional scaling default, and I seriously assume it's for short-sighted marketing reasons. 2x scaling is the sharpest & clearest - best for eyes - setting possible, and it's a shame they hide that option.

Personally I use a third party tool to keep the resolution at the 2x scaled (so 1440x900), as otherwise I get major eye strain.

> You can adjust the scaling if you're really bothered by fractional scaling.

Yes you can, but if you change it from the default then the fonts are either too big or too small.

All Macs have fractional scaling and AFAICT most people seem to have it on. For example my Macbook Pro has a native resolution of 2880x1800. The default OS resolution is 1440x900 (so 2x) but I have it set to 1680x1050 or 1.714

It looks fine and I see none of the issues you mention.

A big difference with Window though is that this scaling happens at a very low-level. The OS tells apps they are on a 2x display at 1680x1050, the OS then scales that 2x display (3368x2100) to 2880x1400. The DPI told to apps does't change on Mac.

The DPI does on Windows and because of various other poor? choices has some of the issues you mention

That's not really accurate for Windows. There's multiple forms of DPI scaling depending on what the application understands:

There's applications that don't understand it at all, in which case the system has the application render at 96 DPI and then scales it up. However, there is a an enhanced mode that was added partway through Windows 10's life which can adjust GDI+ drawing calls to render at the correct size for the target monitor. This can help a lot with making these applications render sharply.

There's applications that understand system-wide scaling. Applications in this category are told the scaling level of the primary monitor when they start up and will continue to render with that scaling even if the system's scaling level is changed or the application is moved to a monitor with a different scaling level set. When the scaling the application started with and the scaling of the monitor don't match, the OS will perform the remainder of the scaling.

Finally, there's applications that understand per-monitor scaling. These will not be scaled in any way by the OS. They receive notifications from the system about DPI changes so they can react to both being moved to different monitors and to the user changing the scaling settings. This was enhanced a little bit into Windows 10's life with a v2 that cleans up a handful of cases that weren't properly scaling.

Actually, on windows apps that implement the DPI awareness API's aren't scaled by the OS at all, and if they implement them properly they even rescale when dragged between monitors of different DPI. So, that is arguably better than the way macOS does it, but only for apps that do the right thing, which isn't all of them. And when they don't implement it correctly, the outcome of OS-level scaling is often worse than on macOS.

This doesn’t really make sense. Your computer is still using all of the pixels on the screen (unless there is a GPU problem), it’s rendering everything bigger so that 2X pixels are used on a 2X screen. The OS isn’t scaling 1680x1050 bitmaps to 2880x1400, unless the apps are somehow producing bitmaps directly.