Display recording for 3 hours, iMac screen turned purple/crashed


New Member

Tried to record a longer video of my display, showing my work process in Photoshop that I would later speed up to a timelapse video. About 3 hours in to the recording my iMac screen turned purple and essentially crashed, which made me restart the computer and unfortunately lose my recording (Recorded with .mp4 as output which does not save when a crash occurs).

My iMac had plenty of memory to spare and fairly decent specs:
Year: 2015
3,2 GHz Intel Core i5
AMD Radeon R9 m390 2 GB Graphics
32 GB 1867 MHz DDR3

My OBS record settings were set to:
Rate Control: CBR
Bitrate: 2500 Kbps
CPU usage: Veryfast
Encoder: x264
FPS value: 6

Does anyone know what might be the problem? Could it be GPU or CPU overload somehow?

Appreciate all the help I can get as I am completely new to this and have no experience with recording my screen or using OBS for that matter.