iMac normal temperature

Something is wonky with the TG Pro Utility or the way that you have it setup.

The CPU temp. is going up and yet only the HDD fan speed is increasing...? In addition the elevated HDD fan speed may actually be starving the CPU Fan from getting enough fresh air to properly cool.

I don't have or use TG Pro Utility, but it seems like there should be a way to only increase the CPU fan to help keep the CPU and GPU cool.

If not, then I suggest that you uninstall the TG Pro Utility as per the dev's instructions and try MacFanControl.

https://crystalidea.com/macs-fan-control

You failed to mentioned that you replaced the HDD with a Samsung SSD from the get go.

Yes the 2010 27" iMac requires the OWC SATA cable with a thermal temp. sensor to properly control the HDD fan.

https://eshop.macsales.com/shop/memory/iMac/2010/DDR3_21.5_27

FWIW 50 to 60C is normal for that year model after it has been running for awhile and 80 to 90C in not uncommon when you are running Photoshop.

While I have used other apps to monitor system temps & voltages on occasion, I typically use Macs Fan Control as it is easier to use when I'm diagnosing a system so I am not sure how well TGPro works overall although I believe I have used it on occasion (if it is free that is).

The information in the screenshot from Macs Fan Control looks good although the "Platform Controller Hub Die" appears it may be a bit high compared to all the other values, but it has been years since I worked on a 2010 model. Most Macs have most of the temps close in value (for those that get extremely hot under load).

Most Intel Macs will idle around 35ºC and run under light to mid load at 65ºC or so, and under heavy load around 95ºC with most Intel Macs reaching a temp around 100ºC-105ºC before the CPU becomes throttled to idle speeds (usually 800MHz). This never really changed over the years for the Intel Macs.....the later models just got to 100ºC much faster than the older models since the later Intel CPUs just run hotter.

Keep in mind that when macOS boots, the system may be doing a lot of work so the system could get warmer than the normal idle temps of 35ºC. Most times third party software is the reason why computers run hard & hot. You may want to run the third party app EtreCheck and post the complete report here so we can examine it for possible clues.

How to use the Add Text Feature When Posting an EtreCheck Report - Apple Community

You can also run the Apple Diagnostics to see if any hardware issues are reported. The Apple Diagnostics are usually pretty good at analyzing a Mac's cooling system for issues, but it will expect a drive temp sensor to be present.

Some Samsung SSDs tend to have compatibility issues with some Macs...usually it is the EVO series, but I don't recall the exact models (several years ago there are posts on this forum where people posted issues with particular Samsung SSDs from the 840-860 ranges IIRC). I would suggest checking to see if the Samsung SSD has any firmware updates available:

https://semiconductor.samsung.com/consumer-storage/support/tools/

Operating temperature: 50° to 95° F

It's unlikely parts are available. Certainly Apple won't work on it.

That refers to the temperature of the surrounding for operation - not the temperature of the Mac.

True, I don't happen to have a 2010 Mac handy to check its temperature.

Have you vacuumed out the vents lately? Especially if you smoke or your cat lounges around the computer.

genikifor wrote:

Im using TG Pro

There a around 20 temperature sensor and three fans in a 2010 iMac.

Which temperature sensor is giving you 70° C - 80° C?

Are all three fans running?

genikifor wrote:

So far i have just replaced the gpu thermal paste and placed pads on the gpu's memory chips. I will vacuum the fans and place new thermal paste on the cpu. But at the moment when the iMac is idle, im getting a temperature reading of 70° C-80° C... isn't that too much?

In addition to bad thermal paste, the heat sinks and tubing could be plugged with dust, cracked or warped and not sitting flat across the CPU and GPU.

If and when you go back in, blow out the heat sink and tubing, then inspect for cracks and make sure that it is not warped.

What third-party utility are you using to check the 2010 iMac's temperature?

There a around 20 temperature sensor in a 2010 iMac and three fans.

Which temperature sensor is giving you 70° C - 80° C?

Are all three fans running?