I/O seems to be the big one. The M1 has Thunderbolt support, the A18 Pro does not. This would majorly limit the resolution of external displays this MacBook could drive, for example. And the base-model M1 was already pretty limited in that capacity already.

Apple has a history of gating external displays behind higher price points. Seems reasonable they’d do it again.

Sure but that doesn’t affect software compatibility which was what the person I responded to was talking about.

There’ll be hardware compromises of course, but software should run fairly uniformly.

There’s definitely some underlying differences seemingly I/O focused that impacts what apps can do beyond simple lack of thunderbolt.

For example Elektron a company that makes synths has some software that runs on Macs and are porting it to iPad. They have it running in beta at conferences. It does audio/data/midi of sorts of USB. They have explicitly stated it will only work on M chips for some reason related to underlying OS limitations.

It’s also my understanding that apps in the App Store need to be explicitly enabled by developers for A & M series compatibility. So there’s something different enough to allow devs to disable / enable.

You can’t gate support on the App Store to specific hardware configurations, only platforms.

At most you can make apps available to iOS or iPadOS separately but you can’t restrict the store listing to any category of iPhone or iPad device.

You can list capabilities your device needs but what falls under those capabilities is at Apple’s discretion.

My understanding from Elektron is they are gated by this: https://developer.apple.com/documentation/audiodriverkit

"Note AudioDriverKit is available on macOS for Intel and Apple Silicon devices, and on iPadOS for devices with an M-series processor."

Maybe they are idiots, maybe the docs are out of date, maybe theres alternate methods.. but it does seem at some point there was/is an A/M series software ability differences in iPad OS.

Like I said, you can gate by capabilities but not by hardware.

I was referring to your last paragraph about the supposed explicit compatibility settings in the App Store per hardware. That is not a thing. Your example is specifically a capability, and one that requires PCIe, therefore needs thunderbolt.

Apple themselves may gate those capabilities behind different product classes, but as a developer you cannot. That in turn makes it very difficult to know specifically why something isn’t supported.

For example you can connect DACs and controllers to non-M iPads https://support.focusrite.com/hc/en-gb/articles/360012532199...

There are also capabilities that diverge in other axes like newer A series chips support things where an M series doesn’t. Hardware raytracing was an example of that for a while. Or still is because there are different gens of M series chips for sale.

Don’t quote me on this but I think the A series also lacks support for virtualization.