Apple M3 Pro Chip Has 25% Less Memory Bandwidth Than M1/M2 Pro

They will compare to the generation of products that yields the largest expected number of potential buyers.

The largest expected number of potential buyers equals "the probability of upgrading when properly advertised to" * (multiplied by) "the total number of macOS users currently owning the hardware of the generation in question".

Where "the probability of upgrading when properly advertised to" depends on how big the jump is, not only in performance, but cumulatively with every other change made to the product. It also depends on how old it is as people are more likely to make another expensive purchase if the previous one was long time ago, just distributing financial burden over time.

And where "the total number of macOS users currently owning the hardware of the generation in question" is merely measured as Apple has direct access to those statistics at any time.

For instance, perhaps the probability that an M2 user will upgrade is only 10%, given how recently M2 released, and how small the difference between M2 based products (as a whole, not just performance of the SoC) and M3 based products is. And perhaps there is 10 million of M2 users. Expected number of potential buyers is 10M * 0.1 = 1M.

Then perhaps the probability that an M1 user will upgrade is 30%. And perhaps there is 20 million of M1 users. Expected number of potential buyers is 20M * 0.3 = 6M.

Then perhaps the probability that an Intel user will upgrade is 40%. And perhaps there is only 10M of Intel users. Expected number of potential buyers is 10M * 0.4 = 4M.

Therefore: most focus is given to comparing to M1. Second tier amount of focus (only mention in speech occasionally, and show on charts) is given to comparisons with Intel. And third tier amount of focus is given to comparisons with M2 (never mention in speech, but do show on charts). Give 0 focus to anything else to keep the total amount of information presented manageable and avoid getting negative results by confusing and overloading people.

There is nothing malicious here. Just practicality which in this case, dare I say, benefits not only Apple themselves, but their users as well: those who are most likely to feel the need to upgrade as is will receive the most direct and clear information on what they will get out of it.

This is all blatantly false and the exact opposite is true.

> The M1 doesn't really benchmark in pure CPUs tests much higher that the Intel chips it replaced

It does. See Cinebench 2024 ST at https://www.cpu-monkey.com/en/compare_cpu-apple_m1_pro_10_cp... : M1 Pro is 1.6x faster than Intel Core i9-9880H installed in the latest (2019) 16" Intel MBP (see the table at https://en.wikipedia.org/wiki/MacBook_Pro_(Intel-based)#Tech...).

> Instead, most of the felt responsiveness on the M1 comes from the insane memory bandwidth.

False. Extra bandwidth is there for and meaningfully improves the performance of the GPU, not the CPU. CPU can not even access all of that bandwidth in Apple M-series designs in the first place:

"While 243GB/s is massive, and overshadows any other design in the industry, it’s still quite far from the 409GB/s the chip is capable of. More importantly for the M1 Max, it’s only slightly higher than the 204GB/s limit of the M1 Pro, so from a CPU-only workload perspective, it doesn’t appear to make sense to get the Max if one is focused just on CPU bandwidth."

(source: https://www.anandtech.com/show/17024/apple-m1-max-performanc...)

Furthermore, even within the bandwidth actually available, it's just a matter of fact that extra bandwidth barely if ever really makes a dent in CPU limited (as opposed to GPU limited) applications. See https://youtu.be/omumzW1AtGE?t=500 as an example of one of the studies on the overall subject.

> a boost from the lower latency

False. M-series systems have slightly _higher_ system memory to/from CPU latency, and drastically higher system memory to/from GPU latency (especially compared to other iGPU solutions).

See https://www.anandtech.com/show/17024/apple-m1-max-performanc... for the CPU side: 111 ns for M1 Max CPU to DRAM.

See https://www.anandtech.com/show/16680/tiger-lake-h-performanc... for the same data for Intel i9-11980HK as a ballpark comparison point: 101 ns. Apple's results are basically inline with everything else in the industry, and are in fact slightly worse on latency.

For GPU side, see https://chipsandcheese.com/2023/10/31/a-brief-look-at-apples... :

"DRAM access takes more than 342 ns at the 128 MB test size. Going further sends latency beyond 400 ns, perhaps due to TLB misses. M2 Pro thus has higher DRAM access latency than AMD’s Phoenix, which has similar memory access latency to recent discrete GPUs."

You will see: DRAM latency from M2 Pro's iGPU is up to 475ns, while iGPU on AMD 7840HS peaks (on the bad side) at 270ns. M2 (non-Pro) does better than M2 Pro peaking at 330ns or so, still roughly 20% worse than AMD.

I'm sorry, but the exact negation of everything you said is in fact true.

Intel flubbed the die shrinks several years in a row, but from 2015 it was pretty obvious that whatever apple was designing for wasn't enough. There were better thermal solutions in thinner, cheaper laptops. The fan didn't even draw air over the CPU in the last intel MacBook air. I opened one and really tried to figure out if there was some 4d chess going on, but no. The fan did nothing. It just started spinning fast making noise for no reason. I even did the old incense test. Next to nothing was being pulled over the CPU heatsink.

It was spectacularly bad by design. This would not have been sufficient even if intel had delivered.

The pro models were better but still awful. It wasn't a matter of fitting things in. It was by design.

I have apple products. I like them. But even being charitable I can't come to any other conclusion that they just didn't care to deliver a good product.

I don't have the impression Apple would intentionally cut the performance like that if they can't also make you pay for an upgrade that alleviates the bottleneck. Want a reasonable RAM & storage capacity? Pay for the upgrade. Want more IO without dongles? Pay for the Pro model. Want a 120Hz screen for smoother drawing? Pay for the iPad Pro.

If it was intentional I'd expect Apple to have a more expensive Pro Max Ultra tier with actually good cooling, and then a year later they can pretend they invented a new paradigm of CPU cooling that works even in the cheaper models. There's no upside for them if cooling just sucks in general, and their switch to a more energy efficient architecture is clearly motivated by this problem.

What I’m saying is that the older models (like the 2016 MacBook Pro Touch Bar) didn’t throttle very much and were thermally acceptable. Fast forward to Intel’s newer chips in 2018-2019 and the same chassis was much more limiting to the newer processor SKUs.

Here’s an article: https://appleinsider.com/articles/19/05/26/tested-thermal-th...

> Apple's 2016 MacBook Pro chassis was designed at the latest, in early 2016. We got the first glimpse of it in a photograph in May of 2016. It looks like Apple is sticking with a four-year chassis design, so it's entirely possible that this is the last year of this enclosure.

> We aren't expecting a thicker machine.

> We've also said this before — we think Apple got hosed by Intel, when they were gearing up for the 2016 MacBook Pro enclosure in 2015. We know that in 2015, Intel was promising delivery of 10nm process Core chips well before now. With any luck, Intel will finally deliver on its promises for a die-shrink that was expected nearly three years ago which will help alleviate the situation further. Or, maybe the next will be ARM-based — we don't know.

Apple’s stop-gap 16” model would prove to be thicker, and the article correctly hinted at a future ARM system.

This quote is important context because Intel had been promising lithography advancements that were delayed.

In 2016 Apple designed a chassis that they wanted to keep around for the next several years, but Intel basically didn’t deliver on their stated roadmap. There was no way to update the system without pushing the thermal solution to its limits or partially redesigning the thing.

As far as thermal performance on 2015 systems (pre-USB-C), those designs are so old that I don’t think replacing Intel was on Apple’s near-term radar.