Saving die space also has no effect on power efficiency, beyond reducing the total transistor count. I'd be very surprised the x86-specific decoding logic makes up a significant area of your typical die. Maybe you'd make the processor 3% more efficient? Something like that?
I’m not sure how it works in the modern era. But back in the day there was also a performance cost when you had a mix of 16 bit code and 32 bit code in memory. I don’t know how it would be in 32 bit vs 64 bit.
And being able to get away with less RAM also improves battery life because keeping RAM refreshed uses energy - again a bigger factor on mobile.
The smaller the die, the less energy it uses. You can also use that space for efficiency cores.
Like I said, if the 32-bit stuff is getting used, that's an argument not remove the support.
> And being able to get away with less RAM also improves battery life because keeping RAM refreshed uses energy - again a bigger factor on mobile.
Memory allocation exists purely at the software level. The hardware doesn't understand whether a particular region has been allocated or not; the only difference between an allocated page and an unallocated one is that the former appears in the OS's VMM data structure as allocated (i.e. it's just more bits in memory). The power consumption of RAM scales with the total cells installed, not with how much the OS has decided is "in use".
