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puma1552

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Original poster
Nov 20, 2008
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The past couple weeks here at work with my Rev B. base MBA, where they haven't turned the AC on yet (it's 26* C in the staffroom here at the school I work at), my Air has been spinning 6000+ despite the computer temps only being mid-upper 50s.

Yeah, it's warm in here, and it's definitely humid, but the computer's temps simply aren't high enough to warrant 6200 RPMs...ideas why?
 

macJC50640

macrumors regular
Jan 19, 2009
188
0
Is the fan ALWAYS spinning at the same speed? What are you doing on your computer, anything graphics/CPU intensive?
 

puma1552

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Nov 20, 2008
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It just happens here at work where it's humid and I only have one or two browsers and skype running.

I have SMC--that's what I'm using to monitor the fan speed (not adjusting it though, just monitoring).
 

puma1552

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Nov 20, 2008
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What are you doing in your browsers and Skype? I'd give a SMC reset a try first.

Just forum browsing/email. Nothing intensive like Flash or anything.

Did both a PRAM and SMC reset, getting the same thing. Currently 56*C and 6200 RPM.
 

Nak

macrumors newbie
Feb 4, 2008
28
0
Portland, OR
puma1552,

I have the following in an AppleScript that runs at startup to set the max fan speed. I've found that 5000rpm max is a good tradeoff between noise and cooling efficiency.

=========================
-- Set max fan speed
-- 4000 RPM => 3e80
-- 5000 RPM => 4e20
-- 6000 RPM => 60e0
do shell script "/Applications/smcfancontrol/smcFanControl.app/Contents/Resources/smc -k F0Mx -w 4e20"
=========================

Note that when you sleep your Mac, the max setting is reset. To get around this, you have to install SleepWatcher (http://www.bernhard-baehr.de/) and put the shell command above in a .wakeup file in your home directory. This way when your Mac wakes up from sleep, the command is rerun to set the max fan speed.

Works great for me.

Nak
 

puma1552

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Nov 20, 2008
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At home in the AC it workes fine, upper 40s and 2000 RPM at idle.

Right now at work again it's 53*C and 6200 RPM again.

I realize it's hot so the computer should run hotter with a higher fan speed, but it makes no sense to be spinning at 6200 RPM if the computer is holding constant at 53*C.
 

ayeying

macrumors 601
Dec 5, 2007
4,547
13
Yay Area, CA
At home in the AC it workes fine, upper 40s and 2000 RPM at idle.

Right now at work again it's 53*C and 6200 RPM again.

I realize it's hot so the computer should run hotter with a higher fan speed, but it makes no sense to be spinning at 6200 RPM if the computer is holding constant at 53*C.

You're only reading the CPU temp. You're forgetting the other temps such as GPU, Ram, Motherboard temps, enclosure temp, ambient temp. They all effect on how the fan is running.
 

orpheus1120

macrumors 65816
Jan 23, 2008
1,430
57
Malaysia
Are you plucked into any AC supply? If so, the fan will kick in at a higher rpm.

At 55 celsius, the fan shouldn't run at 6200rpm.
 

puma1552

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Nov 20, 2008
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You're only reading the CPU temp. You're forgetting the other temps such as GPU, Ram, Motherboard temps, enclosure temp, ambient temp. They all effect on how the fan is running.

That's a good point as well.

They finally turned on the AC here at school, and now my fan is back down to 2000 RPM, with the temp hovering around the same as before, as it should be.

I wonder if the fans have some dependency on humidity since as soon as the air got drier in here the fan speed went back to where it was supposed to be?
 

puma1552

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Nov 20, 2008
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Alright so in the past couple hours it's been seeming to cycle--it will go down to 2000 for a while and then shoot up to 6200 for a while, and then keep doing this cycle, though it will spend a good 20-30 minutes at full blast and then maybe 5-10 at where it should be.

It's cool in the staff room here.

Should I take it in? Logic board?
 

Miker2k

macrumors regular
Feb 2, 2009
135
0
Is there a utility that will produce a graph of Temps vs Fan Speed over time? I know that iStat will show me what's going on now but I would be curious to see a graph over the course of 24 hours.
 

Barbie

macrumors regular
Jan 28, 2009
188
0
ocean
Wirelessly posted (iPhone 3.0: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_5_7; en-us) AppleWebKit/530.18 (KHTML, like Gecko) Version/4.0.1 Safari/530.18)

That is precisely what's up with my Rev B solid-state Air too !!!

The processor isn't doing anything intensive whatsoever, but the fan speed rockets to around 6200 RPM, and according to iStat, once it ran at 6250 RPM - unbelievable

That was during a heatwave here, but since the heatwave concluded, the Air is blowing fine.

Barbie
 

ayeying

macrumors 601
Dec 5, 2007
4,547
13
Yay Area, CA
Alright so in the past couple hours it's been seeming to cycle--it will go down to 2000 for a while and then shoot up to 6200 for a while, and then keep doing this cycle, though it will spend a good 20-30 minutes at full blast and then maybe 5-10 at where it should be.

It's cool in the staff room here.

Should I take it in? Logic board?

Is the system idle or are you doing anything? If its idling, and its at 2500RPM, it shouldn't shoot up to 6200 for no apparent reason.
 

MontyC

macrumors member
Jun 17, 2009
56
7
London Uk
I had a MBA and it *always* ran at 6200 RPM fan speed unless I am in a super cold air conditioned room. I now have a MacBook Pro and that hardly ever reaches 2000 RPM. I think it is the reality of the MBA design
 

puma1552

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Original poster
Nov 20, 2008
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Is the system idle or are you doing anything? If its idling, and its at 2500RPM, it shouldn't shoot up to 6200 for no apparent reason.

just have maybe one or two browsers open looking at forums, and maybe skype...that's it.
 

Teh Don Ditty

macrumors G4
Jan 15, 2007
11,306
8
Maryland
If you're running skype, or more to the point using the video aspect you will be taxing the processor thus increasing the fan speed.

I don't have an MBA, but on my MBP 15" and UMBP 13" my fan speeds will increase according to the temps (60-70C).

As others have said download smcfancontrol.
 
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