High Sierra dual monitor sometimes doesn't work and when it does cursor lags and screen glitches

[alexnmt]

I recently updated to high sierra from a very stable El Cap installation.

With this update, I've been having issues seemingly stemming from the second monitor. The first is an Acer24 inch connected via DVI, the second is a Samsung 40 inch TV connected via HDMI. Often when I turn on the computer in the morning, the HDMI second screen says there is no input signal, and will only start working after a few restarts/shut downs and waiting a while. If it works straight away, if I restart, the second monitor sometimes doesn't work. It is seemingly random as to when it works and when it doesn't.

When the second monitor is working, the mouse cursor freezes every few seconds for a moment. I've also noticed that occasionally the second screen will flash with a white glitch. Very occasionally, the computer will randomly freeze altogether and not respond to anything, though this happens a lot less since I installed Lilu and IntelGraphicsFixup.

System definition is iMac14,2. I can post configs/logs if they are helpful.

Forgive me if this has been solved elsewhere but I couldn't find a fix after searching the forums, but if I missed it, please point me in the right direction.

Thanks for your help.

 

[guitarcal]

I recently updated to high sierra from a very stable El Cap installation.

With this update, I've been having issues seemingly stemming from the second monitor. The first is an Acer24 inch connected via DVI, the second is a Samsung 40 inch TV connected via HDMI. Often when I turn on the computer in the morning, the HDMI second screen says there is no input signal, and will only start working after a few restarts/shut downs and waiting a while. If it works straight away, if I restart, the second monitor sometimes doesn't work. It is seemingly random as to when it works and when it doesn't.

When the second monitor is working, the mouse cursor freezes every few seconds for a moment. I've also noticed that occasionally the second screen will flash with a white glitch. Very occasionally, the computer will randomly freeze altogether and not respond to anything, though this happens a lot less since I installed Lilu and IntelGraphicsFixup.

System definition is iMac14,2. I can post configs/logs if they are helpful.

Forgive me if this has been solved elsewhere but I couldn't find a fix after searching the forums, but if I missed it, please point me in the right direction.

Thanks for your help.

Were you able to solve this? I am seeing somewhat of a similar issue! Here is the thread. https://www.tonymacx86.com/threads/dual-quadro-4000-slow-sluggish.257109/

Thanks