iMac 5k with ridiculous high temperatures

Mines the same running at ridiculous temps 100 Degrees most of the time on all cores when doing short video conversions. The fan goes full pelt but doesn't cool it enough ...I'm also running with a 1Tb SSD which i thought would help keep the inside temperatures down. seriously thinking of taking it back because that heat can't be good for it!!

If you are not comfortable or do not like how hot your iMac runs,

First do a web search and install a temperature monitor on your new iMac.

I am not sure what is available for OS X El Capitán and later Mac OSes.

For temps, anything over 70 degrees C (160 degrees Fahrenheit or higher ) is bad.

I always use a software fans control for my older 2009 and 2010 iMacs.

Again do a web search for a software fans control that is compatible with OS X El Cap.

I use SMC Fans Control, but there maybe a couple of other internal fan controllers that maybe better for you.

SMC Fan control always keeps the fans spinning all the time on my older iMac.

With SMC Fans Control, I have the RPMs set (between1500-1700 RPMs) to so my iMac's power supply and the GPU diode (these are the hottest running hardware components in an iMac) stay, more or less in the 45-50 degrees C range. This brings my hard drive and CPU temps to under 40 degrees C (less than 100 degrees Fahrenheit).

Running the internal fans faster, also, have reduced the operating temps of my internal hard drive and bulit in optical drive to around the 42°-43°C (approx bewteen 105°-110°F) which is about 10°-12° cooler.

The key is not to run the internal fans at speeds that turn them into dust sucking vacuums.

iMacs get hot!

This still seems to be the case even in the new and newer slimline iMac models.

VERY HOT!

Apple is too fixated on thinner and thinner computer chassis and quiet operation than on whether the rather excessive internal heat build up inside any Mac computer is enough to cause early, premature component failures.

Heat is THE ENEMY of all small electronic component hardware!

I DO NOT like the idea of my iMac slow roasting its internal components, AT ALL!

iMacs get WAY TOO hot for my comfort and too hot to not suspect that many iMac hardware component failures might be heat related. Especially premature failure of the optical drive, internal hard drive AND early GPU or Logic board failures.

A cooler iMac is a happy, longer running iMac.

Besides implementing a software internal fans control,

Go out and buy like a small desktop fan ( something like the fans made by Vornado) and place it behind the back near the area of your iMac that gets the hottest.

This is what I have done and it allows for my iMac to run cooler.

You won't have a silent operating computer any longer, but your iMac will definitely be running cooler and, perhaps, lengthen its longevity.

Good Luck!

Welcome to Apple Support Communities

You have got a 27-inch 5K iMac. 5K is in bold because you should know that you are playing a game while using a extremely high resolution, so your GPU is working extremely hard and it gets hot quickly. In order to reduce the GPU temperature, just go to System Preferences -> Displays, and choose a lower resolution before you start playing the game, or do this in game settings. The thin design of the 5K iMac also helps getting higher temperatures, so fans work harder (looking at the picture you attached, fans are working at a very high speed).

Even when you are using the iMac for normal tasks, remember that the resolution is very high and the GPU works harder than, for example, a non-Retina 27-inch iMac, so temperatures will be always higher. However, you say that temperatures are between 45 and 75ºC, and those temperatures are safe.

I recently purchased an iMac 5k i7 AMD m295x. I have the same "issue". Running a game of any kind, even at a lower resolution, spikes the GPU diode temp to over 100º Celsius. I am bringing it in to an Apple Store this weekend to go over it with a tech, but I'm strongly favoring returning it while I'm there. Temperatures this high can't be good for the longevity of this machine. Even with AppleCare, I don't see how it would last more than 3 years under medium use. Those kind of temperatures will warp the board over time unless Apple is hiding something.

Would be interested to know what you ended up doing.

100 degrees Celsius (212 degrees Fahrenheit ) is just about the boiling point for water.

Seems ridiculously high temperatures to me, too!

WTH?!!!

Way too high a temp unless Apple is making the Logic board base materials out of something that is designed to handle the much higher temps.

I do not really know.

All I know is that high heat and "slow roasting" is the eventual premature death for any small micro electronic components.