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RoastingPig

macrumors 68000
Original poster
Jul 23, 2012
1,606
66
SoCal
Hello everyone i have 2010 21'' 3.06 i3 imac and its been in use for quite a while now and I've noticed in istat menus that the cpu fan never surpasses 1200rpm. Even in heavy task it will not surpass that 1200rpm barrier and get to like 150ish degress. i did install smc fan control a while back but since then have unistalled it and even fully reinstalled the os from scratch. I have reset the pram before but still wont crack 1200rpm. Is this imac stupid or whats going on?
 

Intell

macrumors P6
Jan 24, 2010
18,912
433
Inside
That's normal and done by design. If the fans need to go faster to remove heat, they will. There's no need to manually increase the fans speed as the heat won't damage anything.
 
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GGJstudios

macrumors Westmere
May 16, 2008
44,465
833
Hello everyone i have 2010 21'' 3.06 i3 imac and its been in use from quite a while now and I've noticed in istat menus that the cpu fan never surpasses 1200rpm. Even in heavy task it will not surpass that 1200rpm barrier and get to like 150ish degress. i did install smc fan control a while back but since then have unistalled it and even fully reinstalled the os from scratch. I have reset the pram before but still wont crack 1200rpm. Is this imac stupid or whats going on?
Your fans may or may not spin faster. They do so only as necessary to keep temps in a safe operating range. 150F/65C is not particularly hot, so it's not surprising that the fans aren't spinning faster at that speed.

If you're not already doing so, use iStat Pro (free) or iStat Menus ($16) to get accurate readings of your temps, fan speeds, etc., rather than relying on your sense of touch or sound. A forum member has posted a copy of iStat Pro that has been "tweaked" to enhance compatibility with Mountain Lion. You can download it here.

The Intel processors used in Macs are designed to automatically shut down to prevent damage if they truly overheat. CPU Tjmax = 105C (221F), GPU Tjmax = 100C (212F) on i3, i5, i7 processors. (Source: Intel)

Unless there is a rare defect in a Mac, most temps are well within the normal operating range, considering the workload being put on it. Websites with Flash content, games and other multimedia apps will put higher demand on the CPU/GPU, generating more heat. This is normal. If you're constantly putting high demands on your system, such as gaming or other multimedia tasks, expect temps to rise and fans to spin up accordingly. It's just your Mac doing its job to maintain temps within the normal range.

It is also quite normal for your Mac to become extremely hot to the touch during intensive operations. The aluminum body transfers heat more effectively than other materials used in computer casings, so you will feel the heat more. This doesn't indicate that it's overheating and will not harm the computer to be hot to the touch.

Your fans are always on when your Mac is on, spinning at a minimum of 2000 rpm (for MBPs) or 1800 rpm (for MBAs, MBs and minis). iMacs have 3 fans with minimum speeds in the 800-1200 range. They will spin faster as needed to keep temps at a safe level.

If your fans are spinning up without increased heat, try resetting the SMC.
(PRAM/NVRAM has nothing to do with these issues, so resetting it will not help.)

The intake and exhaust vents are in the back of the computer near the hinge on all Mac notebooks (except the new MBP with retina display, which has intake vents along the sides at the bottom). The iMac vent is a slot on the back near the top of the computer. Make sure the vents remain unblocked to allow your computer to perform at its best.

Learn about the fans in your Mac
Apple Portables: Operating temperature

For Flash-related issues:
 
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RoastingPig

macrumors 68000
Original poster
Jul 23, 2012
1,606
66
SoCal
Thanks. if i do go the manual route whats a good Cpu Fan rpm while doing heavy task like video conversion or playing games. I've seen the GPU get really hot and would like it to chill out a bit during games like sims3
 
Last edited:
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GGJstudios

macrumors Westmere
May 16, 2008
44,465
833
Thanks. if i do go the manual route whats a good Cpu Fan rpm while doing heavy task like video conversion or playing games. I've seen the GPU get really hot and would like it to chill out a bit during games like sims3
You can't manually set a fan speed. With apps like smcFanControl, you can adjust the minimum speed, but not set a specific speed. You really don't need to do that, as your Mac will automatically manage temps and fan speeds. It's quite normal for temps to get hot under heavy workloads. When your Mac starts shutting down due to temps, then you need to look at it. Otherwise, just relax and enjoy your Mac.
 
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RoastingPig

macrumors 68000
Original poster
Jul 23, 2012
1,606
66
SoCal
i worry about the heat because i've had the display replaced twice due to the smudges wich are said to be dirt solidified due to heat and the smudged appear around where the GPU heat-sink is and i am now out of warranty and would not like them to reappear
 
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Intell

macrumors P6
Jan 24, 2010
18,912
433
Inside
i worry about the heat because i've had the display replaced twice due to the smudges wich are said to be dirt solidified due to heat and the smudged appear around where the GPU heat-sink is and i am now out of warranty and would not like them to reappear

Those smudges were not caused by heat. They were caused by dust, being blown in from fans. The new iMacs have a vastly improved screen that is better sealed against such dust. Increasing the fan speed will likely increase the chance of getting those smudges.
 
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RoastingPig

macrumors 68000
Original poster
Jul 23, 2012
1,606
66
SoCal
damn. My screen is currently immaculate and i guess its time to sell this comp i got a 500gb 840 in here so its pretty fast for the average user. Ive been wary about pulling the trigger on the i7 680mx fusion imac because i have a retina macbook and i dont think i need anything more. but if them smudges come back im screwed since ive already had the lcd replace 1 time out of warranty and i dont think they would do it again for free.
 
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shoefer

macrumors newbie
Mar 23, 2013
2
0
Texas
shutting down

ok... I've had my iMac since 2007, it's the 20" intel duo, I've upgraded the RAM to 3gb and upgraded the HDD to 1tb, everything has been working great until about the last 2 months. Now when using the iMac it will shutdown at random during use. I never hear the fans speed up but suspect it's due to heat...??? I've done the SMC reset several times and it still kept shutting down. I installed SMC fan control and bumped the fan speeds up and it has not shut down again...??? I tried the Derman iMac Fan Control but the CPU and GPU temperatures never worked and only read 32 degrees farenheit. I like the Derman idea in that it speeds the fans up when needed and lets them slow down when not... I've been told SMC only sets a specific speed and that's it. Is there a program like Derman's that is updated? I have 10.7.5 and Derman's website says it's only designed to work with 10.4.
Can anyone tell me how to get the CPU and GPU temps to read with Derman, or is there another program out there that will work???
 
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