Size vs performance?

[Richard_Vivanco]

Hi
Im working in a exterior scene with corona 1.5.2 and max2017.  I have 24gb DDR3 +core i7.
My scene have a lot of corona proxys (grass, trees). It have 1.8 mllions of polygons.

When i render at 1920x1080 px  with 6 minutes in the time limit  configuration, it render ok
But when i increase the size to 3700x2081 i need to increase the time limit to 3 hours... its toooo slow
I test with PT UHD and PT PT, nothing changes.  The other values are by default
Any idea how can i optimize the render configuration? or its a hardware limitation?
Thanks

[Richard_Vivanco]

Well, i remove de displacement map of the ground material and now the render time its fine again, it works very fine at 4K resolution.
But i have the dude why at 2K i dont have problems with displacement map....
 

[Ludvik Koutny]

Because you start running out of RAM, so it starts to page memory to hard drive, which is 49816819196519841621181 times slower than RAM ;)

[sprayer]

Because you start running out of RAM, so it starts to page memory to hard drive, which is 49816819196519841621181 times slower than RAM ;)

how it depends of displacement? It made calculation before rendering. and 24gb i think is more then enough for 1.8m poly scene with displacement. i think it's some buggy displacement, i saw some strange pixelation with some displacement maps at zoom in

[romullus]

how it depends of displacement? It made calculation before rendering. and 24gb i think is more then enough for 1.8m poly scene with displacement. i think it's some buggy displacement, i saw some strange pixelation with some displacement maps at zoom in

I can easily create 2 polygon scene with displacement that wouldn't fit into my 16 GB RAM, so it isn't hard to imagine situation where 24 GB won't be enough, especially given in mind that displacement is render resolution dependant.