Annoying whine on iMac after SSD upgrade

[Ludwwwig]

Hey!

So, in preparation for Catalina, I thought I would upgrade my 21.5" 2009 iMac with an SSD. I bought a Kingston SSD A400 for about $40 and went ahead yesterday and performed the upgrade. My iMac was very dusty and I used a lot of compressed air on can to blow it clean. I swapped the Superdrive (which seemed to never be able to read CDs anyways) and closed up the machine. Everything booted fine but I immediately noticed a quiet high pitch sound. You can't really hear it while playing music but it's very annoying when you just want to sit down and focus. I first thought I might have damaged a fan but I'm not so sure anymore. I also noticed that when running off the SSD, it would just randomly have a read/write of 0 KB/s for about 20 secs and then go back into full function. At this point the system is basically unusable. I have read about this problem on the internet and there seems to be a firmware update for the SSD, but since my iMac doesn't support AHCI, I can't install it.

Now, the SSD might be faulty or just need a software fix. But the weird thing about my iMac is the sound. When I boot up my mac using the alt-key, the high-pitch noise is clearly noticeable. But, if I decide to boot into Windows which is installed on my 500 GB internal HDD, then the noise immediately ends when the Windows boot process starts. If I decide to boot into High Sierra on my HDD or Catalina on the SSD, then the noise is present. What is going on?

Could it be that the Windows fan profile is different to the one used in macOS and hence the whine is avoided? I tried running the fans at different RPMs in macOS but nothing would eliminate the noise. Or could it be that since the SSD is formatted as APFS, Windows does not give the SSD any power / cpu time and hence the SSD can't create the noise.

Sorry if my post was a bit messy. English is not my first language. I would really appreciate some help on this and would be willing to provide any logs.

Thanks!

 

[TwoH]

Are all temperature sensors present inside the machine? When you swapped your HDD out - it would have used a temperature sensor made specifically for that make of HDD and would not fit in your SSD - so it would not be reading any temperature for the HDD and causing fan ramp.
Possibly windows does not check for this and decides not to ramp the fans.

 

[mmomega]

If you swapped the hard drive for an SSD, then it is your fans spinning WAY up.
This happened to be back in 2009 when I replaced my HDD then and there was only 1 option to take care of it.
I do not personally care for the software solutions but it can take care of it.
For software you have

Macs Fan Control - control fans on Apple computers, also on Windows via Boot Camp

Control fans on Apple computers, also on Windows via Boot Camp. Monitoring of fan speed and temperature sensors. Solve fan noise and overheating problems, iMac HDD replacement

www.crystalidea.com

The one I used before was

eidac

I have several 2009-2011 iMacs and ended up just purchasing this kit from OWC which puts an actual temperature sensor back in the system and allows macOS to control the fans again itself.

OWC Digital Thermal Sensor for 2009-2010 iMac HD Upgrade

Required for any drive installed into the main drive bay of a 2009-2010 iMac, and fixes fan noise and other firmware issues with third party hard drives.

eshop.macsales.com

Personally over the years I had many instances where computer upgrades, either on Mac or Windows would break the software and it was a reinstall or troubleshooting involved, so I decided to just install the physical sensors so that I did not have to spend time or worry if an update would break compatibility with the software.

Hoping one of these options can help fix your problem.
If you want to try a software solution I would try the first listed one just to see if the fan is even the cause. If so, then move on to the hardware solution if you choose.