Cycles Blender Crashing my Workstation upon rendering

[coccomerro (ovia)]

Hello,
I have a simple scene with 20mil tris inside and only one of them is being subdivided at render time 2x
Everything is at default - and it works ok when I view in viewport shaded but when rendering it F12 (trying actually) my ram goes all the way up, my cpu as well.

I ticked CUDA in System for both my GPU
rendering with cpu or gpu does not change this
changing tiles and cpu priority/affinity the same

my rig
x99a rog strix + 64gb ddr4 + i7 6900k + rtx 3070

Maya + Arnold rendered this in few minutes and barely got at a third of the resources, so it must be some setting I am missing.

[Jerry_PM (Jeremy Zimmermann)]

Do you receive the out of RAM Message after starting the Rendering or what happen?

Btw, is the background 3D? The stones etc?
If you dont see it in the final rendering, why even render?

[coccomerro (ovia)]

No Out of Ram warning, no warning of any sorts it just stalls to crash!
yes the hdr is grass+stones+sky

[KAUSTIK]

OK so your HDR is not upping your polycount.

I would check how high the render settings for Subdivision surface modifiers are. Also, maybe deactivate caustics since you don’t seem to have the “real” ones turned on at all. I wouldn’t recommend Fast GI approximation since you have mirror surfaces facing each other. And I think you could turn all your light paths down to 4

If it still doesn’t work, especially after managing your polycount, you got yourself a bug. :')

[KAUSTIK]

Oh, and if you are using adaptive subdivision, try deleting the Brick/stone right underneath the camera

[coccomerro (ovia)]

so the subdivision happens only on the main SLAB (the central stone piece that has the book and ring on top) the rest are optimized proxies.

[coccomerro (ovia)]

thanks - deactivating caustics
fast GI - was off already
light paths you mean - max bounces?

[coccomerro (ovia)]

[KAUSTIK]

yes exactly.

turn total to 4 as well. But I think that’s not it.