So, check out this useful “Compare Mac Models” page (h/t @gruber). Scroll down to the “Compute” and compare the stats. Go on, do it, I’ll wait. See anything that makes you go WTF?!? I did.
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2/ It’s the Memory Bandwidth numbers, “Up to 170 GB/s” for the M6, “Up to 614 GB/sec” for the M5 Max/Pro models. This is a big deal? Computers pull data from memory into the CPU, crunch it, write it back out. But they can crunch many times faster than the memory can deliver it. So the effective performance depends a *lot* on memory bandwidth.
3/ The kind of heavy-duty work these things are designed for (LLMs, big-video, etc) all tend to work with huge blobs of data, so in many cases the memory bandwidth is the limiting factor. Old programmer mantra: “All computers wait for data at the same speed.”
@timbray the M6 is inferior in almost everything, but it's also half the price of the M5 Max...
I think the 6 stands for "2026"
@johnefrancis Huh… I'd have thought the performance increased as the number after the “M” did.
@timbray Apple’s ”M” chips come in multiple sizes for (most) generations. (Replace n with 1-6.)
* Mn - The plain, no-suffix M chip. This is the smallest and cheapest, with the narrowest busses and the least cores, etc.
* Mn Pro - The next size up: more cores, wider busses, more PCIe lanes, etc.
* Mn Max - The biggest “single chip” M chip (though the M5 Max does use separate CPU and GPU dies now).
* Mn Ultra - Two Mn Max chips stuck together, so double everything the Max has.
@timbray Rumor (and reality, so far) is that M6 will be the ONLY “6”-series M chip, so no M6 Pro, M6 Max, and M6 Ultra. Apple is skipping straight to the M7 generation.
(Also, the M4 series never had an “Ultra” chip.)
So, a plain M6 is much smaller/weaker than an M5 Pro, let alone an M5 Max or Ultra.
But the M6 does have 2x the “Neural engines” of the M5 Pro and M5 Max, so it might be able to win a very specifically designed benchmark on that.
@timbray maybe the M6 Max will be more comparable, if Apple is doing that...but it probably won't be $2k
@johnefrancis @timbray It's rumoured that there will be no M6 Pro or Max. Possibly due to difficulty / lower initial yields with the new 2 nm processor node. Will be M7 generation that have the next Pro and Max.
@johnefrancis @timbray I believe you're correct about it being a mismatch comparison. Along with the number of cores, Apple has been touting memory speeds for Max. But wow does this ever make the difference clear!
4/4 Now, this is tricky stuff. There are multiple levels of cache between the CPU and memory, and we really have no idea what those numbers on the Apple page mean. But wow, I’d sure want to find out before I ordered one.
@timbray
Aren’t the differences mostly down to the number of cores in each? The M6 here has 12 CPU cores / 12 GPU Cores, while the M5 Pro/Max has 18 CPU cores / 40 GPU cores.
Not really comparing apples with apples.
@IanOB oops
@timbray Worse things happen at sea
