[bluegreyred]

In a way they already do.

All current Macs include a T2 chip, which is a variant of the A10 chip that handles various tasks like controlling the SSD NAND, TouchID, Webcam DSP, various security tasks and more.

The scenario you mention — a upgraded "T3" chip based on a newer architecture that would act as a coprocessor used to execute ARM code natively on x86 machines — seems possible, but I don't know how likely it is.

[dr_zoidberg]

Yeah, but what would be rationale? They want to avoid x86 as a main CPU, so either you'd get an "x86 coprocessor to run Photoshop" (let's go with the PS example here).

Or you'd have to have fat binaries to have x86/ARM execution, assuming the T3 chip would get the chance to run programs. Now either program would have to be pinned to an x86 or ARM core at their start (maybe some applications can set preference, like having PS be always pinned to x86 cores) or have the magical ability to migrate threads/processes from one arch to another, on the fly, while keeping the state consistent... I don't think such a thing has ever even been dreamed of.

I don't think there's a chance to have ARM/x86 coexist as "main CPUs" in the same computer without it being extremely expensive, and even defeating the purpose of having a custom-made CPU to begin with.

[yellowapple]

An x86 coprocessor is not that outlandish. Sun offered this with some of their SPARC workstations multiple decades ago, IIRC.

Doing so definitely would be counterproductive for Apple in the short-term, but at the same time might be a reasonable long-term play to get people exposed to and programming against the ARM processor while still being able to use the x86 processor for tasks that haven't yet been ported. Eventually the x86 processor would get sunsetted (or perhaps relegated to an add-on card or somesuch).