Since i haven’t noticed it on any of the popular forums, YT channels and tutorials, (am hopefully assuming that…) most likely the majority of blender’s user base is also familiar with it as am i (probably also the reason why there’s not much mentioning of it around), but… (let’s not be so enclosed within self - i don’t like being selfish, but am always talking from my own experience… the tricky mind of consciousness :o) This is for those who don’t know it yet, read on…
“Why?”
Use it to save time rendering animations.
“How?”
Set it under Render > Display: Keep UI
&
Don’t open UV/Image Editor window. Keep the mentioned window closed the whole time while rendering (or the process will slow down).
“Anything else?”
Even better optimization is, if you learn, teach yourself about (batch)rendering from command line.
Effect is most prominent with animations (multiple rendered frames) especially with large formats. The higher the resolution the more time (& memory) is preserved.Even more w/o Blender window being open (using CLI).
And just a single frame for proof (images are 50% scaled down from original 2607x2135):
Model: Stone black 1 by 3dhdscan
DCC: Blender 2.79b pigeon
OS: Windows 7
PS
To note.
First, it appears there’s a bug using HDRI textures on Lamps (Area, Spot) - they randomly flash. For now with all 2.79 blender instances i tested with (official + dailies).
Second, dailies also show a nasty bug when Motion Blur is being used along with Persistent Images. As if motion is exaggerated to the point of the whole image getting unrecognizably blurred.
Am investigating further, but posting here for any confirmation or further information as it will help me make precise report.
TIA & happy blending