M4 Mac Announcements

[NotEntirelyConfused]

In general the M4 chips seem to use more power across the board though. And I’ve seen several reviewers note concordant increases in fan noise as a result in some models, but the same or actually less fan noise in others, but more throttling. It seems to depend on what Apple decided for that model.

Right, but other reviewers, or posters in the MR thread who seem to have their heads on straight (plenty of participants did not), did not note corresponding levels of fan noise. There seems to be a large difference in the experiences people are reporting. This is what I was talking about - some people are not reporting significant fan noise even when the fan is running at higher speeds.

There are also those 3rd party tools to control fan speed. That’s another solution to those bothered by the fan noise (as long as it isn’t coil whine). TG Pro? I think there others too.

Right, and some people in that MR thread have used those tools successfully. Others just... whined.

When it comes to noise, case size is critical. With a larger case and attendantly larger heatsinks you can dissipate thermal energy less noisily because you can get higher airflow at lower air velocity. And you can use bigger, slower-moving fans.

Case size is only critical if it's relevant - that is, if it's actually a factor, because it's being used as a heat sink and radiator, and because a larger fan is being used, taking advantage of that larger case.

It's not clear to me that any of those are true in the case of the old Mini. That is, the fan in the old Mini was not as large as the entire case, and in fact may not be any larger than the fan in the new mini- that's something I don't know, and nobody reported exact sizes in that MR thread. Does anyone here know? I also don't have any useful info on how effective the old Mini was at using the case as a heat sink and radiator.

Also, FWIW, the standard return window is 2 weeks (with the holidays they have until Jan 8

Right, that's what I was talking about - all the pissing and moaning was from people who, at that time, would have had two months or more to return the new Mini since holiday return rules were already in effect.

 

[Jimmyjames]

To add more noise to the data, I purchased an M4 Pro Mini. 14c cpu, 20c gpu 64GB and I can say my experience is that it is silent most of the time. If I use Cinebench to test the cpu, then after a minute or two the fans become audible. I measured using my Apple Watch from right next to it and it was about 48/49db. From a foot or two away it was around 43db. Only the cpu running at 50% or higher will incur any kind of audible fan noise. The gpu doesn’t seem to cause it to spin up at all. Playing games or doing gpu benchmarks hasn’t yielded noise at all.



PS. It’s awesome. I am coming from a 2018 Mini and the difference is staggering.

 

[Citysnaps]

To add more noise to the data, I purchased an M4 Pro Mini. 14c cpu, 20c gpu 64GB and I can say my experience is that it is silent most of the time. If I use Cinebench to test the cpu, then after a minute or two the fans become audible. I measured using my Apple Watch from right next to it and it was about 48/49db. From a foot or two away it was around 43db. Only the cpu running at 50% or higher will incur any kind of audible fan noise. The gpu doesn’t seem to cause it to spin up at all. Playing games or doing gpu benchmarks hasn’t yielded noise at all.



PS. It’s awesome. I am coming from a 2018 Mini and the difference is staggering.

Thanks for the heads up - appreciate it. I'm considering an M4 Mini for my 8 outdoor security video cameras and home automation that has been running on a 2019 Intel i7 Mini 24/7 for the last five years, and produces a lot of heat. Will be nice going with an M4 Mini knocking that (and electric bill) down, and also processing the video streams at higher frame rates.

I'm also considering an M4 Pro Mini for a dedicated X-Plane simulator computer that drives three large displays.

 

[mr_roboto]

It's not clear to me that any of those are true in the case of the old Mini. That is, the fan in the old Mini was not as large as the entire case, and in fact may not be any larger than the fan in the new mini- that's something I don't know, and nobody reported exact sizes in that MR thread. Does anyone here know?

I got curious, so I decided to find out. Apple posts images that can be used for this as part of their repair manuals. I used images showing each mini in its mostly assembled state with the fan visible. This let me use the overall case width (a posted spec) to calibrate my pixels per inch scale for each image.

I compared the plain-M4 mini to the M2 Pro mini. Plain M2 mini has a smaller fan than M2 Pro. Maybe should've used the M4 Pro mini, but I don't think the fan size differs between M4 and M4 Pro, only difference is whether the heatsink uses copper fins and a bigger heatpipe.

Results (M4, then M2 Pro):
Fan body: 3.3", 3.1"
Fan air intake diameter: 1.6", 1.58"
Fan hub/motor diameter: 1", 0.85"

So, about the same size. If anything, the M4 fan is slightly bigger.

On the other hand, the airflow path in the M2 mini is a bit simpler.

I also don't have any useful info on how effective the old Mini was at using the case as a heat sink and radiator.

No reason to think either is effective at this at all, because in both cases the aluminum shell is airgapped from the SoC and SoC heatsink.

 

[NotEntirelyConfused]

Thanks, that's very useful!!

No reason to think either is effective at this at all, because in both cases the aluminum shell is airgapped from the SoC and SoC heatsink.

Right, but that means the case will sink and radiate heat based on what transfers from ambient air. That's not nothing. But is it significant? Will the larger case make a meaningful difference? I don't have good instincts for this, but my guess is no.

 

[mr_roboto]

Right, but that means the case will sink and radiate heat based on what transfers from ambient air. That's not nothing. But is it significant? Will the larger case make a meaningful difference? I don't have good instincts for this, but my guess is no.

It shouldn't be a significant effect.

Heat flow can be modelled with equations that are essentially the same as simple Ohm's law calculations, just with slightly different units. The motivating force that creates currents is temperature rather than voltage, and the current unit is watts (joules per second) instead of amps (coulombs per second).

Every material (or interface between materials) has a characteristic thermal resistance (units: degrees kelvin per watt). This means you can draw up thermal circuits modeling all the paths that heat can flow in. Just like electric current flow through resistors, heat flow through a path is proportional to delta-T divided by resistance (delta-T being the temperature difference across the ends of the path being analyzed). Lower resistance implies higher flow.

SoC -> heatsink -> forced airflow -> vented to atmosphere is a path that's engineered to be very low resistance. SoC -> (a bunch of paths) -> mostly motionless internal air -> aluminum shell -> atmosphere is a much higher resistance path, with most of that resistance being the airgap (motionless air is a good insulator, this is why double paned windows are so much more energy efficient than single paned). Most heat generated by the SoC will be rejected to atmosphere through the low resistance path.

 

[KingOfPain]

To add more noise to the data, I purchased an M4 Pro Mini. 14c cpu, 20c gpu 64GB and I can say my experience is that it is silent most of the time.
(…)
PS. It’s awesome. I am coming from a 2018 Mini and the difference is staggering.

It seems we got the same model (48 GB RAM probably would have been more than enough for me, but I also went for 64 GB; so far I believe I only managed to fill half the RAM and I didn‘t even see any compression yet). I almost posted here when I ordered it (I received it on Friday 13th), but the thread had strayed so far from this topic, I thought it wouldn‘t be interesting anymore.
I switched from a MacBook Air M1 and the difference is noticeable during normal use. For you it must be a much bigger step up.

I can also confirm that it is practically silent.
I believe I heard something when I pushed the M4 Pro to 100°C while testing Xbox emulation, but that could also have been my heating. It definitely is not the sound of laptop fans spinning at full speed that some reviews described.

The company I work for is paying a native English teacher to improve our English once per week.
This week I helped said teacher to reactivate his Apple ID (he thought he didn‘t have one) to get delivery updates after he ordered the basic Mac mini (16 GB, 256 GB SSD). Since he also switched from older Intel models, he‘s also impressed.