I knew persons using the X86 Mac compatibility layer on PPC Macs, and 
was told that there was a noticeable performance hit because the 
emulator (more or less) functioned as an "inner interpreter" for a 
totally different ISA.  The same is true between X86-64 and the 64 bit 
ARM ISAs (along with other architectural differences).  Out of 
curiosity, how similar are the Apple Mac ARM CPUs to the CPU used in the 
Fujitsu Fugaku HPC machine (A64FX 48C 2.2GHz)?

On 12/14/20 12:12 PM, Jon Pruente wrote:
> On Mon, Dec 14, 2020 at 2:07 PM Yasha Karant <[log in to unmask] 
> <mailto:[log in to unmask]>> wrote:
> 
>     For the Apple Mac community:  as is known, Apple is leaving the X86-64
>     platform for an ARM platform.  Will older applications be updated, or
>     will new (and in some cases, newly licensed-for-fee) applications be
>     required?
> 
> 
> The recent releases of macOS went 64-bit only, which cut out a lot of 
> old software. The most recent release that added support for ARM also 
> includes a binary compatibility layer to run x86-64 programs called 
> Rosetta 2, after the similar layer they used when they transitioned from 
> PPC to x86.