iMac (Retina 4K, 21.5 inch, late 2015)
CPU: 3,3 GHz Intel Core i7
Memory: 16 GB 1867 MHz DDR3
Graphics: Intel Iris Pro Graphics 6200 1536 MB
Built in monitor: 21,5-inch (4096 x 2304)
Harddrive: 500 GB SSD
(This is the lastest iMac 21,5" with 4K display)
In two special occations whe whole screen goes balck for about 0.1 secounds.
1) When watching Netflix in Safari
2) When running Windows in Virtualbox
I have only seen it happen in these two ocactions, but it alwasy happen, though it seems pretty random WHEN it happens.
When disabling 3D in Virtualbox I did not see the issue happen.
I have been running a lot of 3D test/benchmark programs to try to get the issue to happen but I can't.
Easiest way is to start Virtualbox and let it just run and move windows around for a while.
I have send sysdiagnose to Apple who say they can't reproduce the issue.
I have cought the thing on video recorded with my mobile phone.
Since it does happen in both Virtualbox nd Safari (whatching Netflix) it can't be program related but must be hardware or driver related.
Since it only happen in these two programs and only seems to happen in Virtualbox when 3D is used I would think driver issue.
I see no error in any system log or program log, so the system seem to think everything is OK.