iMac display target mode bare minimum OS

[peeti]

Hi all, read the forums all the time - finally setup an account just to ask this question since I cannot find a good answer.

I have an older iMac running as an external display to a new iMac. As many of you know - you need a full operating system running on the "display mac" in order to do this...

Since processor cycles = heat and energy waste, I want to configure a bare bones operating system. None of the push daemons, none of the iCloud stuff, spotlight etc - none of it is needed since that Mac just sits there donating its screen real estate.

Is there a guide to Sierra that can walk me through processes safe to disable, how etc? Is there a tool that does this as a single click type operation? I cannot be the only one that thought of this issue. For me, I noticed that my "monitor" is sitting there just getting hot. So at the very least I killed the 5 year old OS install and all it entailed, loaded up a fresh copy of Sierra. But it still gets warmish. May be time to open it up and clean it - perhaps fans aren't running as efficient, but the original request holds regardless.

Many thanks in advance!

 

[ApfelKuchen]

Someone somewhere probably does have a comprehensive guide. Off the top of my head, there are several things you can do.

1) Don't login to a user account on the iMac being used as the display - that will minimize any activity due to login items, etc. Effectively, the login screen is "bare bones."

If you want to go the extra mile, do an erase/reinstall of OS X on the target iMac. No third-party software, no user data.

There's no disk-related work being done while you're at the login screen, and minimal processor activity, so things should be running very cool. Still, the display requires a fair percentage of the system's power, so don't expect the iMac to run any cooler than a standalone display.

 

[peeti]

Thanks - that's as far as I got on my own as well. I want to take it further by killing spotlight and all the daemons that do run regardless of login to update things. Stuff like map push, photo, etc - I ran a check and lots of these processes are loaded and running. While they are idling, they still have to wake up from time to time to see if an update occurred. So if anyone has a pointer to said guide - I'd love to see it. Many thanks!