Curious about the heat from an iMac?

Question

Hello,
I have an 3.4 Ghz iMac i7 8gb Ram that I just purchased. I never really noticed how hot the fan gets on the top of the machine until I touched around it today, and it literally turned my hand red. I don't want to go by touch alone, so I downloaded iStat Pro. I was wondering what the normal temperatures are for the iMac and how hot that vent really should get.

Answer 1

CalebWynn wrote:
Ds Store,
I've noticed on my MBP that the fan idles around 2000 RPM as well and moves from there. I am assuming that because they're different machines, they're going to run at different temperatures.
The MBP have a minimum 2000 RPM fan speed because the fans are smaller and the case if more compact, so the airflow has to be naturally higher.
The iMac can have a slower fan speed in comparison because the case is larger, the fans can be larger and more more air at slower rotation speeds, so I'm not going by that at all.
Far as the CPU's, that's a different animal. Intel makes them and they all have heat tolerances ever since they hit the thermal wall, so it makes economic sense to keep the heat down for both desktop and laptop processors instead of seperate production, economies of scale and all that.
The heat issue is why Apple and IBM split over the PowerPC, they couldn't advance the RISC architecture and keep the heat down for laptops.
Why Sony and IBM made the Cell processor as a game console, due to it's heat. And the Xbox took 3 PPC G5 processors. My old Dual G5 was a hot bugger for a desktop, no way was that going into a laptop, I should have seen the writing on the wall for that and sold before the Intel announcement and recooperated the $10,000 I bascially threw away on a soon to be obsolete platform (dam you Apple!)
So the CPU temps one can get a eyeball on what would be the ideal and 100-120ºF at idle is about right. Mine is about 95-100 F at idle because of the fan tweak.
Now the GPU temps are another story, the iMac has a larger GPU and screen than the MBP's, so it's understandable the temps could be a bit high there, as well as the power box being insdie the case, unlike the MBP where it's a brick on the wire.
I recommend the 1000 increase in minimum fan speed to keep the machine a bit cooler than what your "burning the hand" comment, but I basically see your temperatures as being normal for what you have.
Your concerns are like others who expressed the same, it's more in the "personal preference" zone than a actual problem with overheating.
But I wanted to warn you about the expensive hard drive replacement, sometimes the cheap drives Apple sometimes use die within a few years.