Using iMac 27" with a '20 Macbook Pro 16

Do you want a 27" screen?  Do you have an extra iMac sitting around?  Keep reading.

I'll walk you through how I got my iMac 27" to be used a a Target Display for my 2020 Macbook Pro 16.

Requirements

1) You need an iMac of somewhat recent vintage.  Mine is a 2010 I believe. 
2) You need to ensure it has a Mini Display Port on the back
3) You need to have a Mini Display Port cable - male to male
4) You need a Mini Display Port to USB 3/thunderbolt3 adapter


For #4, I reached out to the trusty web and purchased the ASL All Smart Life USB C to MDP adapter.  For #3, I picked up up online, any will do. 

The iMac does not even need to fully function, for example, if you have a problem where the login in not working or it is not fully booting, it will still function as a monitor. 

This works with an Macbook Air circa 2015 as well.   All you need is to make sure you can deliver the video signal from the source Mac to the iMac with the least amount of adapters.  

It does not work very well with Windows computers, I know of folks who have done it but I never got it to work.  I admit, I don't have a lot of Windows computers and I didn't spend a lot of time on it. 

Largest Drawback - the iMac takes a lot of power and puts out a lot of heat, just to be a display.   It also takes up a measurable footprint.   During the Pandemic work from home, it did provide me with a very high quality 27" display and I got my money's worth.