Does M1Pro Memory Bandwidth change with amount of RAM, size of SSD or # of cores?

[GooseInTheCaboose]

I read M1Pro memory bandwidth can be 200gb/s compared to the M2’s 100.

But is this number constant for all M1Pro configurations? Do you get a higher or lower bandwidth when you have more or less RAM? Or a bigger SSD? Or the lower 8/14 cpu/gpu configurations compared to the upgraded 10/16 core/gpu?

 

[jav6454]

Bandwidth on all CPUs regardless of type is standard speed and will not change from advertised as those speeds are negotiated and sustained by the Memory Controller. The only thing that might is CPU frequency to save power.

 

[GooseInTheCaboose]

Bandwidth on all CPUs regardless of type is standard speed and will not change from advertised as those speeds are negotiated and sustained by the Memory Controller. The only thing that might is CPU frequency to save power.

So, is it the same for all the CPU configurations? (Including the lower end base M1Pro with only 8 cpu cores and 14 gpu cores? Like, did Apple make all the configurations of the M1Pro chips the same, or are they different?)

 

[GMShadow]

Yes, it's the same. The M1 chips with fewer cores are physically identical to the ones with more (in the same class). Chip yields mean that some chips end up with defective components, and rather than throw these out companies simply disable the bad parts and sell them for a lower price.

This is pretty common across the industry, it's not just Apple that does it.

 

[GooseInTheCaboose]

Yes, it's the same. The M1 chips with fewer cores are physically identical to the ones with more (in the same class). Chip yields mean that some chips end up with defective components, and rather than throw these out companies simply disable the bad parts and sell them for a lower price.

This is pretty common across the industry, it's not just Apple that does it.

Oh intersting. Are the lower end chips at least a little cooler-running because of that? Or just...worse? lol

 

[jav6454]

So, is it the same for all the CPU configurations? (Including the lower end base M1Pro with only 8 cpu cores and 14 gpu cores? Like, did Apple make all the configurations of the M1Pro chips the same, or are they different?)

Yup, it stays constant. The memory controller ensures that.

 

[jav6454]

Oh intersting. Are the lower end chips at least a little cooler-running because of that? Or just...worse? lol

Yes and no. If the CPU has issues from the fab process, then the troubled area of the die is disabled via laser. In other words it "eliminates" the core and it receives no power. However, if the CPU was complete and Apple is requesting a chip with fewer cores, then the fab will perform a binning operation. It cordons of the CPU from anything except power.