2009 Bootcamped iMac overheating

What is the rpm (speed) of the fan when Windows is running? Also, what programs are running at startup?

If the iMac would overheat, it would shut down, to prevent actual overheating.
Anyway, what are you actually doing during those high temperature times and what are the fans' speeds?

Since you did not specify the actual iMac you have (there were several options in 2009 ranging from C2D via i5 to i7 CPUs), maybe this can help: Those Macs in their heat - a sine of over-heating? - a short story by Mister GGJstudios

stupididiot said:

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That's when the core0 temp is around 89 C

CPU is Core 2 Duo i5 E7600

I'm doing anything from transcoding (which kicks the CPU to 100%) or just letting it idle. It will always eventually shut down to prevent over heating

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It seems the fans stay at idle speed, thus the high temperatures.
I do not know of any reliable Windows fan speed control application, but many seem to use SMC Fan Control in Mac OS X and set the fans' speed to the fullest and then switch to Windows.

PS: A Core 2 Duo (C2D) is not an i5. The E7600 is a C2D.

2008 imac mtn lion overheating

Hi All - my imac has crashed a number of times- the cpu shut down with glowing screen and since I appreciate others offering tips on their apple problems this is what I did which has dropped the heat at the problem area at the top left dead air space in the computer
I had a copper aluminum heat sink with dispersal vanes from a dismantled windows tower and secured it to the back of the imac with gorilla tape- has dropped the cpuheat by 15 degrees
I also boosted smc fan control speeds
I ground a convex curve into the heat sink copper base on my lapidary grinder to fit the imac back
I like my apple but dont like apples denial of the problem- I already had to replace my HD out of my own pocket which failed and I think the overheating caused it but the dealer just pooh poohed my concerns
kj
thanks all