2018 Mac Mini fans at full blast when screensaver kicks in

[djc6]

I use the "Message" screen saver - it puts an apple logo and a message (the machine's hostname) onto the screen, they move around periodically. When the screen saver kicks on, the fans run as full speed. If I nudge the mouse or something to wake the monitors up, the fans go silent 20 seconds or so later.

Why is the most basic screensaver tasking the CPU so much the fans come on?

 

[djc6]

I enabled ssh on my mac mini so that I could ssh into it from another machine while the screensaver was running and see whats up.

What I found running top command was that Finder was using 100% of CPU during screensaver operations. So I looked up how to troubleshoot this issue, and one suggestion was to go to Login Items and try and cleanup "Allow in the Background" items. I did find a lot of them from old pieces of software, some I no longer even had installed. So I whittled down the list and the list of "Open at Login" and no longer am seeing this 100% Finder CPU when screensaver is running. Not sure which item I purged was the culprit.

 

[djc6]

Woke up to the mac mini's fans absolutely at full blast again.... and yes, the screen saver has the cpu pegged 100% when I ssh in and run top:

/System/Library/Frameworks/ScreenSaver.framework/PlugIns/Computer Name.appex/Contents/MacOS/Computer Name -AppleLanguages ("en-US")

Why do I use screen saver? because waking monitors from sleep is so unreliable on the mac mini! I figured the screen saver that bounces the hostname around the screen would be the least CPU intensive.

Maybe there is also a memory leak - top claims screensaver is using 48.9% of my RAM. Everything else is <1% of system RAM (I have no applications running). I have 16GB installed.

 

[nathan_reilly]

I had found this exact same behavior in my computer a few years ago. I even found that while running a preview of the screen saver in System Preferences (not even full-screen!) I got similar 100% CPU pegging. I reinstalled MacOS (wiped fresh) and the issue went away. Kinda dumb imo.

 

[djc6]

I think I may have found a solution. Tuesday morning, I pruned my "Allow in the background" items in Login Items settings and I haven't heard the fan since then. There were "Allow in the background" items for all kinds of old pieces of software that I had deleted from Applications folder years ago.

 

[Chuckeee]

I think I may have found a solution. Tuesday morning, I pruned my "Allow in the background" items in Login Items settings and I haven't heard the fan since then. There were "Allow in the background" items for all kinds of old pieces of software that I had deleted from Applications folder years ago.

Glad you found a solution, to bad you were not able to find the specific culprit.

 

[djc6]

Glad you found a solution, to bad you were not able to find the specific culprit.

Nevermind, solution didn't work, woke up to same problem again today. Fans screaming from screensaver (checked via ssh/top again) and machine is silent 10-15 seconds after stopping screensaver


So I did NOT find the culprit...

 

[djc6]

Just following back after extensive testing. I no longer think the screen saver was root cause of the issue - I think root cause was my pi.hole ad blocker.

I have cnn.com home page as my startup page, and would often just leave browser open when screensaver kicks on.

I have a pi.hole ad blocker on my network which was blocking domains vod-media-aka.warnermediacdn.com and live-media-aka.warnermediacdn.com - in the default ad blocking list, I did not add these domains to deny list.

Something is wrong with javascript on the main CNN.com page where if it can't connect to these domains to fetch mp4 files to autoplay video ads on the main page, it goes into a tight loop requesting them over and over again - quickly accumulating tens of thousands, or even hundreds of thousands of requests in Chrome's Developer Tools depending how long I let it go. This was source of 100% CPU. Once I unblocked domains in pi.hole I no longer experienced this 100% CPU issue.