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AnthonyMouse parent
It isn't the chip which determines whether it's fanless. Basically every modern chip supports power capping and then the power cap is determined by how much heat the machine can dissipate.

What that really determines is multi-thread performance. Fanless laptop that can dissipate the power of one core? No problem. Fanless laptop that can dissipate the power of all the cores? For that you have to lower the clock speed quite a bit. Which is why you see AMD chips on older TSMC process nodes getting better multithread performance than Apple's fanless ones.

The cost/benefit ratio of adding a fan is extremely attractive. The alternative way of doing it is to add more cores. If you have 8 fanless cores at 2 GHz, how do you improve multi-thread performance by 50%? Option one, clock them at 3 GHz, but now you need a fan; cost of fan ~$5. Option two, get 16 cores and cap them at 1.5 GHz to fit in the same power envelope, but now you need twice as much silicon, cost of twice as many cores $500+.

The number of people who pick the second option given that trade off is so small that hardly anybody even bothers to offer it.

Apple continues to do it because a) then they get to claim "see, they can't do this?" even when hardly anybody chooses that given the option, and b) then if you actually want the higher performance one from them, you're paying hundreds of dollars extra for more cores instead of $5 extra for the same one but with a fan in it.


ndiddy
If someone besides Apple made a fanless laptop that had competitive performance with Apple's offerings (i.e. not a $200 Chromebook with a Celeron or a cast-off 5 year old smartphone CPU), I'd absolutely buy one. I got excited when the Qualcomm Snapdragon X was being discussed pre-launch, but then it came out with performance worse than the original M1 and it turned out that Qualcomm lied about giving it first-class Linux support. I really dislike Mac OS, but when I can't use a PC laptop in bed or on a couch or on my lap without it overheating, I'm not able to switch away. It's a shame that the entire PC industry is fine with selling laptops that will overheat when not used on a rigid flat surface.
criddell
I believe the Microsoft Surface Pro 7 is fanless. Sadly, the 8 and 9 have a fan.
AnthonyMouse OP
I mean, you could just buy something that allows you to configure the TDP in software and then set it low enough that the fan doesn't run. You'd be sacrificing a non-trivial amount of multi-thread performance, but that's what the fanless Macbooks are doing anyway.
"The cost/benefit ratio of adding a fan is extremely attractive."

Depends on your metric. A fan makes noise, attracts dirt that needs cleaning, needs more space ...

I really love my fanless devices, even though they never will reach the speed of activly cooled ones.

AnthonyMouse OP
Sure, and you can still find fanless devices, but then they'll typically be the ones not focused on multi-thread performance. And if you don't care about that, e.g. because you're offloading heavy workloads to a server or you just don't do anything compute heavy, then you can find a lot of fanless offerings with low core counts that are actually quite inexpensive. You can get some fanless Chromebooks for under $200.
scheme271
It's a bit old at this point but the pixel slate chromebooks can be spec'ed with an i7 and 16GB of ram. I think they go for under 200 on ebay and are decent if you don't need compute heavy apps.
solardev
Doesn't this miss differences between CPUs in their per-core efficiency?
AnthonyMouse OP
The per-core efficiency of Apple and AMD CPUs on the same process node is pretty much identical. This has become harder to directly compare because they're now using alternate process nodes from one another, but have a look at this chart for example:

https://www.cpu-monkey.com/en/cpu_benchmark-cpu_performance_...

What do we see at the top of this chart? TSMC 3nm (M3/M4), followed by TSMC 4nm (Ryzen 7000U/8000U), TSMC 5nm (M1/M2), TSMC 5nm/6nm mixed (Ryzen 7000H), and then finally we find something made on an Intel process node instead of TSMC.

The efficiency has more to do with the process node than which architecture it is.

It's too bad they don't have Epyc on that chart. Epyc 9845 is on TSMC N3E and that thing is running cores at a >2GHz base clock at less than 2.5W per core.

You're linking to a multi-core benchmark. The story is a lot more in favor of Apple if you look at single-core efficiency, Apple is roughly 2-3x more efficient: https://www.notebookcheck.net/Intel-Lunar-Lake-CPU-analysis-...

And this benchmark doesn't even include M4, which is even more efficient.

AnthonyMouse OP
> The story is a lot more in favor of Apple if you look at single-core efficiency

Your link is comparing the M3 against AMD chips with higher TDPs. Higher TDPs tank "single-core efficiency" because power consumption is non-linear with clock speed. Give a core near its limit three times the power budget and you're basically dividing the single-core efficiency by three because you burn three times more power and barely improve single-thread performance at all, and then that's exactly what you see there.

To have a useful comparison you have to compare the efficiency of CPUs when they're set to use the same amount of power.

mmcnl
Ofcourse, but that's the whole point right? At similar power levels, Apple M-series is a lot faster. The only way for AMD and Intel to compete on performance is by providing more power, but this obviously has a negative effect on efficiency. So with AMD/Intel you have to choose: efficient and slow or inefficient and fast. With Apple you can actually have it both ways.
femiagbabiaka
> The number of people who pick the second option given that trade off is so small that hardly anybody even bothers to offer it.

The number of manufacturers or the number of people? Apple was on the path to laptop irrelevancy before the M series, it doesn't seem clear to me at all that people don't care about noise and heat along with performance.

AnthonyMouse OP
People generally have a priority between noise and heat vs. performance. If you don't do compute-heavy stuff then you might as well have something quiet. If you do, i.e. you're always waiting on the machine, how many of those people want to sacrifice a third of their performance to avoid having a fan?
femiagbabiaka
But it’s not a binary choice:

Performance along which characteristics? How much performance does one need locally? At which point does heat/noise/energy cost become too much for a mobile workstation?

All of these are additional criteria that the M series laptops competes in (and in many cases wins), even amongst programmers who are some of the most compute performance sensitive consumers out there.

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