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synagence

macrumors 6502a
Original poster
Jul 23, 2008
879
0
I installed iStat last night for curiosity .... i ran a render in Terragen2 and observed CPU temps and CPU fan

The CPU crept from 40ish to 70ish but the fan remained constant at 1200rpm

Wonder if the controls for the fans aren't working 100% yet and is causing multiple overheat issues....
 
It has been the same on all iMacs since the introduction of aluminium casing.

CPU and HD fans stay at 1200-ish and Optical at 999-ish no matter what.
 
The fans on my new 20" iMac run at:

1600 hard drive
1200 cpu
1350 optical drive


Can any one else confirm that the hard drive and optical drive fan speeds are indeed that fast?

edit: I did get confirmation that the hd fan also spins at 1600 rpms on the 2.66ghz 24" 2009 iMac. That's quite a bit faster than what the hd fan in the previous gen imacs ran at.
 
The fans on my new 20" iMac run at:

1600 hard drive
1200 cpu
1350 optical drive


Can any one else confirm that the hard drive and optical drive fan speeds are indeed that fast?

edit: I did get confirmation that the hd fan also spins at 1600 rpms on the 2.66ghz 24" 2009 iMac. That's quite a bit faster than what the hd fan in the previous gen imacs ran at.

I'm curious if these speeds are true for all 2009 iMacs. I wonder what made them up those from previous generations..

My 2007 iMac alu runs at these:

CPU 1199
HD 1199
Optical 999
 
I'm curious if these speeds are true for all 2009 iMacs. I wonder what made them up those from previous generations..

My 2007 iMac alu runs at these:

CPU 1199
HD 1199
Optical 999

Yeah that's about what my 2007 24" iMac fans ran at.

I'm a bit surprised.

I figured the 9400M gpu in the new iMacs would need less cooling than a dedicated gpu. DDR3 memory is also supposed to use less energy and thus run cooler. The 2.66ghz cpu has a better architecture so it runs cooler at least if clockspeeds are the same. Optical drive & hard drive shouldn't have changed much.

Still 2 of the fans (hard drive and optical drive fans) run faster in the new iMacs. Maybe they cheaped out on some heatpipes or heatsinks or maybe they figured the old ones were running too hot over the long run.

I do think the back of my 2009 20" iMac feels cooler to the touch than my 2007.
 
Fan Speeds

Cpu - 1912
Hard Drive - 2835
Optical Drive - 990

This is from a iMac 24 3.06 Ghz with 4850 Video playing iTunes with full screen visualizer

GPU Temp got as high as 72 C
Power supply as high as 81 C
NOrth bridge as high as 77 C

Now that is hot.
 
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