cpu rendering and ram usage in iray

Ruphuss

just upgraded my windows home premium to 16gb ram -

thats the limit for this programm

i load a szene for iray rendering thats to big for just gpu usage.

at loading time cpu goes up to 100% ram to 10,5 gb

while rendering cpu goes down to 25% so it stays till end of rendering

now i minimize the render and start a new render with the same scene

ram goes up to 14 gb and cpu at 100% all the time i stop rendering

and shut both rendered images ram goes down to 5gb and cpu near zero

conclusion: if you do not shut your rendered images ram goes up and up much more than a simple image should have

it seems like each time you render the same scene the same ram for this image is added

is this usefull behaviour ? intended ?

mjc1016

Yes, it IS intended...that's how you can pause/resume an Iray render.

Iray does not create a 'scene' file like Luxrender does, so that it can save its progress.  Any progress made is held in memory until the render window is closed.

AndyS

But how does this come:

Mem usage before render: ca. 3GB
Mem usage while rendering: 7.2GB
Mem usage after render: ca. 1.5GB  (Picture saved and closed, workspace still open - so same status as before render)
 

Ruphuss

thank you mjc

so its good to know not having open to much renders

when you render to new window

gpu rendering does the same

stacks up memory

Richard John S

This is interesting. So, given the fact that I only have 8GB of ram some of the Iray memory usage is most likely being written to my hard disk?

AndyS

Seems to be like that.

And even worse: If you want to use the nVidia GPU cards and the needed memory exceeds the graphic card's capacity, iRay quits the GPU usage and returnes to the slow CPU-only render modus.