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Temperatures and Fan Speed

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Phlegethon

macrumors newbie
Original poster
May 10, 2010
4
0
hey dudes,

got a problem, after i bought the new macbook pro 13'':
i noticed that the fan speed is always about 2000rpm... doesn't matter, whether the temperature is at 40°C or at 70°C or 80°C (my mbp doesn't get hotter)... always same rpm.
is that normal? additional info: i downloaded istat menus 3 which has the option to control the fan speed (i deactivated it... no changing... always 2000rpm). did istat crash the internal fan speed control?

thanks for help. and sorry for mistakes in thread.
 
you misunderstood my thread.
i know, that it doesn't get lower. that was not my question. the problem is, that it doesn't get higher. 80°C and still 2000rpm. that can't be normal?!
 
How long did you wait with the temperature at that level? It takes a minute or two for the fans to ramp up to a higher speed. Fully load the processor and then check the fan speeds after a couple of minutes.
 
Phlegethon said:
you misunderstood my thread.
i know, that it doesn't get lower. that was not my question. the problem is, that it doesn't get higher. 80°C and still 2000rpm. that can't be normal?!
Click to expand...

Sorry, your wording wasn't that precise.

Maybe you can also use MRoogle to find the other dozens of similar threads on that issue.

I encountered the same, and thus I'm using the software I linked to in my first post, as it allows me to set the fan speed depending on the temperature. For example, my CPU gets up to 60°C, the fans will spin at 2500RPM, the CPU gets up to 75°C, the spinning of fans amounts to 6000RPM.
 
5 minutes... tested it again with terminal-command: yes > /dev/null

-> 86°C... no fans.
-> 90°C... fans speed starts to get higher (around 3000)

is that normal? 90°C... at around 100°C the cpu will be damaged (heard it ^^... true?)
 
Phlegethon said:
5 minutes... tested it again with terminal-command: yes > /dev/null

-> 86°C... no fans.
-> 90°C... fans speed starts to get higher (around 3000)

is that normal? 90°C... at around 100°C the cpu will be damaged (heard it ^^... true?)
Click to expand...
That's perfectly normal. The CPU will not be damaged at 100°C. It is designed with internal safeguards that will throttle down the processor if it exceeds the maximum temperature.
 
thanks for the answers, guys.
bill gates... i would sneak-hug you for the fast answer. :D big thanks!
 
I recommend you to use smcFanControl you can download it from cent download.
I should say when I install it at first i changed the speed of fan from the (Performance) but it never changed but after I marked (Autostart smcFanControl after login) it work for me nice and make me satisfied, I recommend you put your fan speed at 2500rpm it work nicely.
 
I know this thread is old, but the CPU has a max temp of 105C. I'm not sure if it throttles down performance when it reaches 105C, or shuts off the computer. There was a guy whos MBP would reached 106C-108C under full load, passing the max temps, but not shutting down.
 
Faravah said:
I recommend you to use smcFanControl you can download it from cent download.
I should say when I install it at first i changed the speed of fan from the (Performance) but it never changed but after I marked (Autostart smcFanControl after login) it work for me nice and make me satisfied, I recommend you put your fan speed at 2500rpm it work nicely.
Click to expand...

I use this also and it works awesome!
 
ouimetnick said:
I know this thread is old, but the CPU has a max temp of 105C. I'm not sure if it throttles down performance when it reaches 105C, or shuts off the computer. There was a guy whos MBP would reached 106C-108C under full load, passing the max temps, but not shutting down.
Click to expand...

105 is when it starts the throttle. It shuts off around 120-125.
 
^ That's a good question.

Anyway,here's what's written on volume 2 of the i7-600, i5-500, i5-400 and i3-300 Mobile Processors Datasheet,found here.

6.10 - Error and Thermal Protection
Thermal Trip: The processor protects itself from catastrophic overheating by use of an internal thermal sensor. This sensor is set well above the normal operating temperature to ensure that there are no false trips. The processor will stop all execution when the junction temperature exceeds approximately 130°C. This is signaled to the system by the THERMTRIP# pin.
Click to expand...
 
nonlocal said:
^ That's a good question.

Anyway,here's what's written on volume 2 of the i7-600, i5-500, i5-400 and i3-300 Mobile Processors Datasheet,found here.
Click to expand...

Cool. I wonder about the Core Duo and Core 2 Duo though.

Found it. I edited the URL and replaced i7 with 2duo, and it says.

The processor supports the THERMTRIP# signal for catastrophic thermal protection. An external thermal sensor should also be used to protect the processor and the system against excessive temperatures. Even with the activation of THERMTRIP#, which halts all processor internal clocks and activity, leakage current can be high enough that the processor cannot be protected in all conditions without the removal of power to the processor. If the external thermal sensor detects a catastrophic processor temperature of approximately 125°C (maximum), or if the THERMTRIP# signal is asserted, the VCC supply to the processor must be turned off within 500 ms to prevent permanent silicon damage due to thermal runaway of the processor. THERMTRIP# functionality is not ensured if the PWRGOOD signal is not asserted, and during Deep Power Down Technology State (C6).
Click to expand...
 
I downloaded SMC Fan Control and created different profiles for different situations(hi-def in youtube, editing photos, etc.) and I also adjusted the default speed to 3000RPM, so it never goes lower than that. 1000RPM's make a huge difference the temps are much more stable now.
 
Yes, and look at these screen shots. The arrendale chips have a thermal limit of 100C for the memory controller and GPU, and 105C for the CPU. The screenshots are from Intel and state that the cooling system is suppost to keep the laptop AT LEAST 10C cooler than the max. so 90C and 95C, should be the max. Yes Apple's cooling system is poor enough, that the Core i& went over 100C during some testing, and the C2D over 100C when I tested it. So Yes, Apple can't really cool their notebooks correctly.
 

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ouimetnick said:
Yes, and look at these screen shots. The arrendale chips have a thermal limit of 100C for the memory controller and GPU, and 105C for the CPU. The screenshots are from Intel and state that the cooling system is suppost to keep the laptop AT LEAST 10C cooler than the max. so 90C and 95C, should be the max. Yes Apple's cooling system is poor enough, that the Core i& went over 100C during some testing, and the C2D over 100C when I tested it. So Yes, Apple can't really cool their notebooks correctly.
Click to expand...

The triple-digit temps are a brief spike as the fans ramp up, at least on my machine. Once it stabilizes, it falls down to 80-85, so yes, they do work correctly. Also, there is the old wisdom about CPU heat: If it isn't crashing, you're fine.
 
J the Ninja said:
The triple-digit temps are a brief spike as the fans ramp up, at least on my machine. Once it stabilizes, it falls down to 80-85, so yes, they do work correctly. Also, there is the old wisdom about CPU heat: If it isn't crashing, you're fine.
Click to expand...

Its not fine. The spec thing says that the cooling should keep it 10C lower than the thermal limit. So if it goes past 95C, even for 10 seconds, they blew it. The point is, if it goes over 9%C then the cooling system wasn't designed correctly.
 
The thing people should remember about messing with fans is that the higher you ramp them up. The shorter their lifespan will be. So you might be keeping components cool but your fans may burn out faster than they normally would. Granted, the motherboard,cpu, gpu, etc. are more important than fans but if your fans are shot then the rest of the comp is screwed.
 
ouimetnick said:
[...] So Yes, Apple can't really cool their notebooks correctly.
Click to expand...
True that.
I hit 94C before fans kicked in,only by watching a yt video. Nothing else running. And around 87C in HTML5.
J the Ninja said:
[...] Also, there is the old wisdom about CPU heat: If it isn't crashing, you're fine.
Click to expand...
Yes,but there would obviously be a difference to components lifetime,when running constantly at 85-90C,compared to,say 65-70C.
And I really don't think it's fine running always at the limit (of temps that is,not life).

I wonder if,aside from loudness and perhaps a slight decrease in battery life,increasing fan speeds slightly,would cause a notable shortage in their life. I guess it would. Either way,I believe they should by default kick in in lower temps,and not at the threshold.
 
I have a theory as to why there's a lag time between when the CPU/GPU heats up and when the fans spin up; it's possible that the smc is not tracking the temperature of the silicon itself but rather the temperature of the heatsinks. The fans can do a more efficient job of cooling a machine only if the heatsinks are reliably transferring heat, e.g. blowing air over a hot thing cools it down faster than blowing air over a warm thing.

I don't know if this is the case or not, I've only managed to observe this behavior once.
 
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