IMAC screen goes black constantly
I am actively working when screen goes out, every few minutes; mainly I'm using Mozilla Firefox, Apple Photos and TDS Email. I shake the mouse and things return to normal after ~2 seconds shaking, every time. A year ago, I had a 2009 IMAC and replaced it due to this problem. Either I copied over a bug when restoring data or both computers have this issue. Any solution? I do have about 50K photos stored and wonder if this is the cause.
New IMAC: 21", 2017
High Sierra vs 10.13.3
Hardware Overview:
Model Name: iMac
Model Identifier: iMac18,1
Processor Name: Intel Core i5
Processor Speed: 2.3 GHz
Number of Processors: 1
Total Number of Cores: 2
L2 Cache (per Core): 256 KB
L3 Cache: 4 MB
Memory: 8 GB
Boot ROM Version: IM181.0153.B00
SMC Version (system): 2.39f39
Serial Number (system): C0****7JY
Hardware UUID: *****
[Personal Information Edited by Host]
iMac, iOS 10.3.3