Late 2015 iMac 27 Performance issues

[billyr50]

I recently upgraded the hard drive on this iMac to an SSD (Samsung T7 1TB Portable SSD). After installing the SSD, the. computer was running extremely slow. I also had no video in the Facetime app. I got a message stating that the video would resume once the computer cools down. Installed an in line heat sensor cable I thought would fix the proble. Still got the same message. I'm going to try a different SSD on the chance I got a defective drive, but I don't know if that will solve the problem. Any thoughts? Thanx in advice for any assistance you might provide.

 

[pshufd]

Is the SSD internal or external?

I'd suggest installing Macs Fan Control to see what your thermals and fan speeds look like.

I have a Late 2015 iMac 27 that I bought a few months ago and just run it off an external USB3 SSD and it runs fine.

 

[Nguyen Duc Hieu]

I recently upgraded the hard drive on this iMac to an SSD (Samsung T7 1TB Portable SSD). After installing the SSD, the. computer was running extremely slow. I also had no video in the Facetime app. I got a message stating that the video would resume once the computer cools down. Installed an in line heat sensor cable I thought would fix the proble. Still got the same message. I'm going to try a different SSD on the chance I got a defective drive, but I don't know if that will solve the problem. Any thoughts? Thanx in advice for any assistance you might provide.

Something is wrong with the drive or the USB cable. Sometimes a USB device can only be recognized as USB 1.1 (extremely slow). Plug-out and plug-in again several time may help.
You can check the USB protocol of the Samsung drive in System Preference.