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smcFanControl... Does Speeding Up Fans Speed Up Mac??

Do you run your fans at 2,000 rpm or have you turned them up??


  • Total voters
    27
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olletsocmit

macrumors 6502
Original poster
Jun 24, 2010
296
2
USA
So i have been using smcFanControl app for a while now. The stock speed is 2,000 rpm and i run mine at 3,000 rpm when on battery and 3,500 rpm when plugged in. I just ordered thermal paste & i am going to re-do it on my Mac since its running hot and and i have never replace it yet. so to stay on topic, there is stuff all over the forums. Speeding up your fans is bad, or its good, it they will die in a few years, etc. Is there any solid proof that its really bad for them?

To my real question... does speeding up your fans truly speed the computer up or does it just keep it cooler. I remember back in my "building desktop days", the colder the comp is the faster it runs. Does the fan speed and the mac running colder have any true effect on making it faster??
 

simonsi

Contributor
Jan 3, 2014
4,850
734
Auckland
Running them faster when there is no need just wastes fan life and battery. They are there purely to stop the components overheating. The safety mechanisms are pretty binary (CPU will suddenly throttle to 50%), I'm not sure how variable the turbo boost clock speeds are but at the end of the day the fans will end up on full if needed, running them at a base of higher than 2000 will not be necessary and you will have no benefit from running them at a base of 3000.
 
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CKemahli

macrumors newbie
Jun 1, 2015
4
0
London
I run them a bit higher to keep the laptop comfortable on my lap. With fans on default the computer will hit 80 celsius before firing up fans, running at 2500rpm keeps it around 65 degrees.
 
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simonsi

Contributor
Jan 3, 2014
4,850
734
Auckland
I run them a bit higher to keep the laptop comfortable on my lap. With fans on default the computer will hit 80 celsius before firing up fans, running at 2500rpm keeps it around 65 degrees.
I use TG Pro - easy to set the temps that the fans ramp up at, more sophisticated than just overspeeding them...I'd recommend Temp Gauge Pro
 
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olletsocmit

macrumors 6502
Original poster
Jun 24, 2010
296
2
USA
I use TG Pro - easy to set the temps that the fans ramp up at, more sophisticated than just overspeeding them...I'd recommend Temp Gauge Pro

thanks for the suggestion. I just got this app. gonna give it a shot.
 
Comment

cool11

macrumors 68000
Sep 3, 2006
1,518
137
I wonder how safe is to make adjustments to mbp fans.
Is it completely safe?
Will this actions shorten their life?
I would like to know opinions not only from simple users like me, but even better from apple technicians or computer mechanics.
 
Comment

Crzyrio

macrumors 65832
Jul 6, 2010
1,503
898
I usually only change the speeds to max when I know im going to load the processor. So before starting video encoding or a video game I turn them up. That way it does jump to 100 degrees before they start to kick in.
 
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scaredpoet

macrumors 604
Apr 6, 2007
6,627
342
I wonder how safe is to make adjustments to mbp fans.
Is it completely safe?

No one can ever guarantee that modifying SMC settings out of spec is "completely safe." That said, it's highly unlikely this will hurt anything. Whether it will help anything is debatable though.

If you're not experiencing overheating problems, then tweaking fan settings won't help anything. If your CPU is not overheating, then running your fans higher than spec isn't going to improve performance.

And if you ARE overheating a lot, then smcfancontrol is really just a band aid. The root cause of the overheating needs to be found and addressed.

Will this actions shorten their life?

In theory no. Fans are fans. In reality, if you're operating in a dusty environment, you will need to watch out more often for dust accumulating internally and making sure that gets cleaned out. But that's a given, as dusty environments aren't good for computers.
 
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Toutou

macrumors 6502a
Jan 6, 2015
673
958
Prague, Czech Republic
No, speeding up your fans won't speed up the system. The CPU slows down by throttling when it's overheating - cooling it more at that moment would help. But as it has already reached its max temp limit, the fans are already running at max RPM. There is no reason to increase idle speeds (except for your own comfort). What I do (and find useful) is that I lower the speeding-up threshold so my fans start speeding up when the temps climb above 55°C, which is high enough not to be annoying and low enough to keep the spikes away from 90°C
 
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olletsocmit

macrumors 6502
Original poster
Jun 24, 2010
296
2
USA
These are my settings if anyone was wondering. seem to work great. i am sure i could tweak a little more with some more rules thou...

 
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cool11

macrumors 68000
Sep 3, 2006
1,518
137
Does smcfancontrol makes 'permanent' changes to fan speeds?
Are the modified limits applied, only when I run the application?
If yes, when I do not run the application, will mbp behave with its' default settings?
 
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yjchua95

macrumors 604
Apr 23, 2011
6,725
231
GVA, KUL, MEL (current), ZQN
Does smcfancontrol makes 'permanent' changes to fan speeds?
Are the modified limits applied, only when I run the application?
If yes, when I do not run the application, will mbp behave with its' default settings?
The modified limits are only applied when the app is open. When it's not open, the MBP will revert back to its fault settings.
 
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olletsocmit

macrumors 6502
Original poster
Jun 24, 2010
296
2
USA
its a great app! I used to use smcfancontrol, but i think that TG Pro is much better and well worth the 3 bucks or so
 
Comment

ckWTB

macrumors member
Aug 24, 2014
33
13
Portland, OR
So i have been using smcFanControl app for a while now. The stock speed is 2,000 rpm and i run mine at 3,000 rpm when on battery and 3,500 rpm when plugged in. I just ordered thermal paste & i am going to re-do it on my Mac since its running hot and and i have never replace it yet. so to stay on topic, there is stuff all over the forums. Speeding up your fans is bad, or its good, it they will die in a few years, etc. Is there any solid proof that its really bad for them?

To my real question... does speeding up your fans truly speed the computer up or does it just keep it cooler. I remember back in my "building desktop days", the colder the comp is the faster it runs. Does the fan speed and the mac running colder have any true effect on making it faster??

The short answer is that running your internal fans at a higher baseline speed has the potential to increase performance, as does providing supplemental cooling directly onto the CPU/GPU.

Now for the long answer.

Laptops have cooling systems with a built-in cooling capacity that is typically less than desktop cooling systems. One reason is that laptop have more tightly packed internal components so there is less space for airflow and a greater likelihood that heat from the CPU/GPU will bleed off into other components as well as the entire computer/enclosure. The built-in cooling system typically use one or more small fans connected to a heat pipe that is connected to a heat sink that is connected to the CPU/GPU. This system is designed to primarily cool the CPU/GPU as they are the primary heat generators.

By increasing the baseline speed of your internal fans or by providing supplemental cooling directly onto the CPU/GPU you will remove more heat from the CPU/GPU, which reduces the amount of heat that bleeds off into other components and the overall computer/enclosure. Combining both a higher baseline internal fan speed and supplemental cooling will further reduce temperatures and increase cooling capacity. However, if you are concerned about reducing the lifespan of your internal fans then adding supplemental cooling is a good solution.

With less heat in the system then your computer will have additional passive heat sink cooling capacity available when a heavy/intensive workload is applied and the initial heat spike that occurs before the fan spin up to full speed will also be reduced. Once the fans spin up to full speed then it is only a matter of time before the heat being generated by the CPU/GPU builds up in the system at which point the heat may overwhelm the laptop’s built-in cooling system resulting in performance reduction as the computer throttles processor speed in order to avoid overheating. Since internal fans are already spinning at maximum speed then supplemental cooling directly onto the CPU/GPU will be required to reduce/eliminate throttling and regain performance.

Throttling can happen frequently and the performance reduction can be severe, while the frequency and amount of throttling depends on a variety of factors, such as the laptop model, its built in cooling capacity, the laptop’s CPU/GPU power, the intensity of the applied workload, the duration of the workload, the ambient temperature, and other factors.
 
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olletsocmit

macrumors 6502
Original poster
Jun 24, 2010
296
2
USA
So i turned on my Mac this morning and bam... my "GPU Diode (Analog)" is running over 100C! this has never happened. been using this app for a while now too... i have turned off, let cool, etc. 1 min after turning on mac its super hot? It was not doing this last night and no changes were made...

see below:

 
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dusk007

macrumors 68040
Dec 5, 2009
3,389
63
That reading is just incorrect. Your dGPU isn't even active.
You never really have to worry about GPU heat anyway. Since its TDP is lower than the CPU, the latter always reaches its 100C temp limit first, which means the systems runs at full fan speed or throttles before the GPU goes beyond 90C.
What you see is just an incorrect reading when the dGPU is inactive.
 
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cool11

macrumors 68000
Sep 3, 2006
1,518
137
Better stress a little bit more the fans,
than let the heat be more inside my mac?
The second option is more dangerous I think.
 
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olletsocmit

macrumors 6502
Original poster
Jun 24, 2010
296
2
USA
That reading is just incorrect. Your dGPU isn't even active.
You never really have to worry about GPU heat anyway. Since its TDP is lower than the CPU, the latter always reaches its 100C temp limit first, which means the systems runs at full fan speed or throttles before the GPU goes beyond 90C.
What you see is just an incorrect reading when the dGPU is inactive.

Ok that is what i thought, it may be correct. do i have a bad sensor or something? It happens randomly, it is happening now again for the 2nd time. my issue is that now using TG Pro or another app if its showing its this high my fans will always be running full blast. but if i disable it, and it gets too hot and they dont kick in i am screwed. what shoould i do
 
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olletsocmit

macrumors 6502
Original poster
Jun 24, 2010
296
2
USA
Its just very weird to me that sometimes its red and over 110 and other times in in the 40's lol very confused.

The biggest issue is that you can not use the setting to set fan speed to specific speed when any temp gets over a specific temp now b/c this one is always over 110 randomly. my fans have been running full blast the last 10 min, so i quit app.

what are your guys temps for this? I dunno the dif between the GPU Diode and GPU Diode (Analog)
 
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olletsocmit

macrumors 6502
Original poster
Jun 24, 2010
296
2
USA
ok so i reset my mac and it ran full blast for 20 min or so, just the desktop, i was doing nothing and the gpu analog thing was around 100C. so i got bored and opened a website and boom, slows down and immediately goes down to 43 and stays there, then open this site in def tab and again boom, fans and over 100C again... i also noticed that when it slowed down the GPU Diode that always said N/A turned green and went up to around 44C. and then open a dif site/app and goes back to NA... what the hell.

here is what it looks like 20 sec after my Mac is turned on (just sitting idol and doing nothing):
-- Notice the "GPU Diode" is N/A and the "GPU Diode (Analog)" is hot.


Now here is what it looks like when i opened firefox and went to a website (www.tomshardware.com):
-- Now notice that "GPU Diode" went from N/A to 47C & now is active & the "GPU Diode (Anaolg)" is no longer super hot and red.

 
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dusk007

macrumors 68040
Dec 5, 2009
3,389
63
CPU Diode does not read out when the dGPU is inactive.
When it says anything other than N/A it means you have the dGPU active.
The analog sensor near the dGPU is just confused for some reason when the iGPU is active. It is really nothing to worry about.
 
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zombiecakes

macrumors regular
Jul 11, 2012
200
59
I set the fan speed higher because I didnt like how hot the keyboard gets in the top right corner on the retina MBP, I increased it to the point just below where I could hear it (I think 3500rpm) and it keeps the keyboard cool when on youtube. It doesnt hurt the fans, they will last like 10 years longer than the computer's usefulness even at constant high RPM, assuming Apple used a high quality ball bearing fan then it will last decades.

If your GPU was 100c there would be no mistake because it would burn you.
 
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olletsocmit

macrumors 6502
Original poster
Jun 24, 2010
296
2
USA
CPU Diode does not read out when the dGPU is inactive.
When it says anything other than N/A it means you have the dGPU active.
The analog sensor near the dGPU is just confused for some reason when the iGPU is active. It is really nothing to worry about.
Interesting. My problem is that the analog one is always at either around 43 or around 100-110. So I am not able to use the setting for if any temp excesses a specific temp. And I can't set it at over 115C. Don't want my cpu to ever get that hot before the fans kick in.

So what exactly is the did between the regular gpu diode, the analog one, and the proxi one? Sometimes the analog one is running alone, then sometimes they are both on together

It's just really weird that it was never an issue till 2 days ago. And the fact that opening a new website tab can shoot the temp from 40 to 110 in 5 sec.
 
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olletsocmit

macrumors 6502
Original poster
Jun 24, 2010
296
2
USA
I set the fan speed higher because I didnt like how hot the keyboard gets in the top right corner on the retina MBP, I increased it to the point just below where I could hear it (I think 3500rpm) and it keeps the keyboard cool when on youtube. It doesnt hurt the fans, they will last like 10 years longer than the computer's usefulness even at constant high RPM, assuming Apple used a high quality ball bearing fan then it will last decades.

If your GPU was 100c there would be no mistake because it would burn you.
You saw my pics of my gpu temps. Can you post where you analog one is usually at?
 
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