What's Different between 15-Core and 18-Core Pro CPUs?

[chars1ub0w]

Yes, that was also my concern and one factor that let me order the 15 core M5 Pro in the end... Did you notice that when you order the 15 core version in the online store Apple let's you choose between the 70 W and 96 W power supplies? Instead, if you order the 18 core one, only the 96 W one can be selected. So there must be a difference in power consumption high enough for Apple to configure this differently. I find it remarkable the cut-off between the two choices is right between the two Pro versions (as opposed to more naturally between base and Pro/Max).

This is evidence the M series has outgrown the MacBook Pro chassis introduced with the original M1 edition.
We know a redesign is coming.
We also know the current chassis does not implement the latest cooling tech used in the iPhone.
So, rather than leaving unused compute on the table, I think it's better to skip the stopgap M5 generation.

 

[Alameda]

This is evidence the M series has outgrown the MacBook Pro chassis introduced with the original M1 edition.
We know a redesign is coming.
We also know the current chassis does not implement the latest cooling tech used in the iPhone.
So, rather than leaving unused compute on the table, I think it's better to skip the stopgap M5 generation.

And we know a redesign is coming after than. And we know an M7 is coming after the M6. And we know that an M8 is coming after the M7. And on and on.

 

[chars1ub0w]

And we know a redesign is coming after than. And we know an M7 is coming after the M6. And we know that an M8 is coming after the M7. And on and on.

No, you don't understand my point. M1-M5 used the same MacBook Pro chassis/cooling. M6 will use a different one.

 

[conmee]

No, you don't understand my point. M1-M5 used the same MacBook Pro chassis/cooling. M6 will use a different one.

It will be interesting to see. If you are correct that the M-series has outgrown the chassis, how is that going to work with the rumored thinner design for the upcoming redesign? Do you think the M6 will run cooler/require less thermal headroom than the current M5? Unless there is a significant bump in performance due to 2nm which allows Apple to dial down the GHz, then I'm not sure the M6 will be any better off unless the chassis is bigger than the current chassis, or some other cooling magic is introduced.

 

[chars1ub0w]

I'm not sure the M6 will be any better off unless the chassis is bigger than the current chassis, or some other cooling magic is introduced.

They could put this tech in. The iPhone 17 Pro already has it. Apple says:
“Deionized water is sealed inside the vapor chamber, which is laser-welded into the aluminum chassis. This efficiently moves heat away from the components, allowing for higher sustained performance. The vapor chamber directs heat strategically through the system, where it is efficiently dissipated and released by the forged aluminum unibody.”

 

[Luftkopf]

This is evidence the M series has outgrown the MacBook Pro chassis introduced with the original M1 edition.
We know a redesign is coming.
We also know the current chassis does not implement the latest cooling tech used in the iPhone.
So, rather than leaving unused compute on the table, I think it's better to skip the stopgap M5 generation.

Vapour chambers aren't some magical new golden bullet for cooling! Is there enough heatsink, is there enough airflow? Maybe a vapour chamber will help spread the heat out to a wide, thin heatsink better, but a slimmer laptop is going to have less total capacity for cooling, not more. If Apple wants to improve cooling, they can choose better fan speed curves, and not wait until a chip hits 100ºC to really ramp up the fans. Get them spinning before the chip is too hot, and you can dissipate the heat better.

 

[chars1ub0w]

If Apple wants to improve cooling, they can choose better fan speed curves, and not wait until a chip hits 100ºC to really ramp up the fans. Get them spinning before the chip is too hot, and you can dissipate the heat better.

You can already control fan speed. Before hitting the return button to start the run, you can hit the cooling symbol for fan speed ahead of time.

 

[uller6]

They disable a bunch of cores, likely by fusing them of. It’s possible that the dies fail some tests (or that the binned dies consume more power than un-binned ones, for example, power-binning is apparently common in mobile), we just don’t know.

The CPU is arranged in three clusters of six cores (one prime-core cluster and two medium-core clusters), so it is my understanding that the the 15-core model disables one core per cluster.

This is the way to high yields! If there is highest probability of one CPU defect, just fuse off 1 core in each cluster to insulate you from 1-3 bad cores.

 

[MacTest57]

Interesting discussion...

I'm upgrading from a "binned" M2 Pro 14'' and have just ordered the "binned" M5 Pro 14''.

Here's my chain of thought...

I really like the 14'' form factor and value the fact my M2 Pro is perfectly quiet and doesn't heat up (still suffering from my i9 trauma I guess 🙂.

I had been pondering for a long time whether to choose the M5, M5 Pro 15 core or M5 Pro 18 core. I really don't need the GPU power of the Max.

One thing Apple does to segment them is memory: the M5 has max 32 GB, the 15 core M5 Pro has max 48 GB and the 18 core M5 Pro has max 64 GB. My M2 Pro had already 32 GB, I wanted to upgrade, so that ruled out the M5. At this point options left were:

- M5 Pro 15 core, 48 GB
- M5 Pro 18 core, 48 GB
- M5 Pro 18 core, 64 GB

Now I noticed that for M5 Pro 15 core 48 GB the online Apple store (Italy) offers a choice between the 70W power brick and the 96 W one.

However, for the M5 Pro 18 core choices, only the 96 W one can be selected. My M2 Pro came with a 67 W power supply. So somehow my overheating-i9 trauma flared up again. I (maybe irrationally) feel happier knowing my 14'' can dissipate those 67 W already so 70 W shouldn't be a problem in the same kind of chassis.

Also, for the M5 Pro 18 core the FOMA to not go the full way to 64 GB is kicking in... Those + 3 cores and + 24 GB RAM end up being + 450 EUR. Paying more for something not really needed and risking worse fan noise / heat was tipping the needle to the M5 Pro 18 15 core, 48 GB in the end.

Of course we're MacRumors forum users so we way over-think these things, I guess 🙂

-- Chris

Hey, I'm thinking about making the same upgrade for the exact same reasons. Have you bought the binned M5 Pro 14? Is it as quiet / cold as the M2 Pro was, or do you notice a difference?

 

[conmee]

Hey, I'm thinking about making the same upgrade for the exact same reasons. Have you bought the binned M5 Pro 14? Is it as quiet / cold as the M2 Pro was, or do you notice a difference?

I tested a 14” base M5, 14” binned M5 Pro, and 16” 18-core M5 Pro. Ran more than a dozen benchmarks. The only time I got the fans to spin up on any of them were some 3DMark graphics benchmarks (the ray tracing Steel Nomad test for example) and I ran two x86 benchmarks (one used Rosetta and one was in a Win11 virtual machine).

My conclusions? If you don’t do lots of intense graphics (gaming/rendering), the 14” base M5 fan (only has one) never goes on. And when it does, because it only has one fan, it is quieter than the other two models (about 52 decibels at 100% fan vs 58 decibels for the 14” binned M5 Pro and 65 decibels for the 16” 18-core M5 Pro - coincidentally the 14” binned at 100% fan was the same loudness as my 2019 15” Intel MBP at 100% fan, and the 16” M5 Pro was loudest - but all the M5’s almost never come on or audible unless doing heavy sustained workloads unlike the Intel which would spin up if you looked at it wrong lol).

If you are prioritizing quietness above all else, the 14” base M5 will be the quietest of the three models I tested even at 100% fan, and as long as no very demanding work is involved, the fan simply never gets audible.

The 16” is also very quiet. It has the most thermal headroom with larger fans and larger heat sink, so it takes really heavy processing or longer sustained workloads to get the fans going. But when they finally get going they will be the loudest. But it will be very infrequent.

Finally, the 14” binned M5 Pro which is the model in question in this comment I found that the fan came on more frequently (but mostly inaudible) than the 16” and came on sooner than the 14” base M5. Because it has more CPU/GPU cores than the base M5, some benchmarks (and thus workloads) will get the fans to come in quicker in a 14” chassis than if the binned M5 Pro were in the 16” chassis. BUT… all that said, it will probably be just as quiet as a 14” M2 Pro. Yes, it draws more power, but also is 2nd gen 3nm vs M2 5nm so there are process improvements that allow for higher performance and power draw. So I wouldn’t let the power brick worry you.

Bottom line: 14” binned M5 Pro should be fine and will be whisper quiet except during high quality settings in Cyberpunk 2077 or rendering large 4K/8K video. If you have severe fan PTSD then the 14” base M5 or a fanless MacBook Air is the way to go. 🙂

 

[Basic75]

And when it does, because it only has one fan, it is quieter than the other two models

Interesting that one fan was quieter than two fans. I would have expected the opposite. Perhaps that's only true for a tower with more space to distribute the airflow to.

binned M5 Pro

All M5 Pro chips are binned, either the "low bin" with 15/16 cores or the "high bin" with 18/20 cores.

 

[conmee]

All M5 Pro chips are binned, either the "low bin" with 15/16 cores or the "high bin" with 18/20 cores.

I don’t disagree. But that’s not how the general population here on MR is using the term. Most people here are using binned as a general term to denote core count. In that context, the M5 Pro 18-core/20-gpu is considered “unbinned” and 15-core/16-gpu “binned” for the Pro offerings (similarly the base M5 offerings with 10 or 8 GPU cores). Folks have been using “binned” as shorthand for fewer cores for a while now. In that sense, only the M5 Max 18-core/40-gpu is the unbinned SoC and everything else in the M5 line is binned one way or another (cores, memory bandwidth, media engines, etc).

 

[conmee]

Interesting that one fan was quieter than two fans. I would have expected the opposite. Perhaps that's only true for a tower with more space to distribute the airflow to.

Yeah I should have also checked the RPMs when I was testing the fan noise, I just used a meter to capture the decibels. I suppose if the single fan ran at the same RPM as the dual fan config, two of the same fan running at the same rpm as a single fan config makes some sense (twice the air flow making a bit more noise). I did notice the one and two fan config in the 14” appeared to use the same size fans, but the 16” had noticeably larger fans.

The great thing about Apple Silicon so far for me is that since March 19th when I received my M5 Pro, the fan has only come on when I purposely ran benchmarks or manually turned the fans on. I run iStat Menus and I haven’t even noticed the fans on low, it simply says 0% fans since I’ve had it. I went to fire up my 2019 Intel 15” and the fan kicked on just booting. Then when I launched a Win10 vitrual machine the fans went to 90% and stayed there for about five minutes then died down. I got so used to that behavior the past six years that I didn’t notice it much. But now going back to the Intel MBP after three months of silence it is kinda shocking how much fan noise I (we) lived with during the 2016-2020 Intel MBP model era.

 

[Luftkopf]

I don’t disagree. But that’s not how the general population here on MR is using the term. Most people here are using binned as a general term to denote core count. In that context, the M5 Pro 18-core/20-gpu is considered “unbinned” and 15-core/16-gpu “binned” for the Pro offerings (similarly the base M5 offerings with 10 or 8 GPU cores). Folks have been using “binned” as shorthand for fewer cores for a while now. In that sense, only the M5 Max 18-core/40-gpu is the unbinned SoC and everything else in the M5 line is binned one way or another (cores, memory bandwidth, media engines, etc).

You’re right, and I hate it. Words have actual meanings! Communication just gets harder with all these shifting definitions. But this is how language evolves, and I suppose I should just shut up about it. It is rather difficult to put up with though.

 

[leman]

You’re right, and I hate it. Words have actual meanings! Communication just gets harder with all these shifting definitions. But this is how language evolves, and I suppose I should just shut up about it. It is rather difficult to put up with though.

Technical meaning and common use meaning are not the same thing. While I sympathize with your cause, I'd say that the common use meaning is more informative. If we adopt the technical meaning, then "it's a binned CPU" doesn't mean much beyond "it's a CPU", while the common use meaning gives you useful piece of information.

 

[Luftkopf]

Technical meaning and common use meaning are not the same thing. While I sympathize with your cause, I'd say that the common use meaning is more informative. If we adopt the technical meaning, then "it's a binned CPU" doesn't mean much beyond "it's a CPU", while the common use meaning gives you useful piece of information.

True. That part of me that rebels against it thinks that there are other ways to communicate the concept that don’t involve misusing words, but I seem to have tipped over into Old Guy now. I just have to let things go, let language evolve how it will, but still explain to the young people that using correct punctuation and grammar doesn’t mean I’m annoyed at them.

I think I’m getting old.

 

[leman]

I think I’m getting old.

I feel you, friend 🙂

 

[akdj]

We don't know - might be purely marketing and cores disabled to create a product stack only. Or could be genuinely defective cores.

M5 starts at $1,699. The M5 Pro 15/16-core is $2,199. Without it, the M5 Pro would start at $2,399 which is a huge jump for customers wanting just a bit more power.

M5 has 10-10 C/GPU cores.
Compared to identical single core scores and demolished by the machine with 50% more multiple cores
And 80% faster going with the 18/20

Regardless both have 20/40 GPU cores so linearly you would see a graphical increase of 2x or 200% faster and 4x or 400% faster using (@ full load)
The 40 core ‘Max’ variants also include double the transcode engine’s doubling the speed of ProRes ingestion and exporting. Both are fast but twice as fast of fours times faster isn’t insignificant
Especially comparing and entry level machine. With limited RAM & chip variant - the fact is that you are almost correct for the majority of the population
However you can make the difference in price up with a single project if you’re in demand as an editor, colorist or continuity director and a several dozen other positions. You make exponentially more than the maxed out 16” MBP editing blockbuster movies or single big brand commercials
So if exporting times take up ⅕ of your day and suddenly only ⅛ of your day you get a free hour to edit or color or mix the audio etc.

Time is my. While most of us will never benefit enough to benefit having the 18/20/128/8 $7,900 machine by any measure. But there’s plenty who do and having a couple new ones is even more beneficial