Hardware question

[miacreed]

Hi all- Hope everyone is well.

Ive recently upgraded my workstation. Im currently working with a 12 core, Ryzen 9 processor and GeForce GTX 1660 Super. I currently have 32gb RAM installed. However, its taking over 9 hours to render a fairly simple scene. According to Task Manager, Im using about 9% of my CPU capacity and 2% of my GPU capacity (image attached). Im at a loss, really.

The same scene was rendered on my laptop (i7 4 core Intel processor, GeForce GTX1080 and also 32GB RAM) in just over two hours. My IT guy (who is not too familiar with Corona) told me that my workstation needs to upgrade GPU- I was lead to believe that Corona was a CPU based renderer that relied more on the CPU than GPU but he argues with me on this. Others have said that its because Im running Windows 10, but, my laptop runs Windows 10 as well and renders fine.

Also: My C: disk (XPG Spectrix S40G 256GB) has 40.7GB free of 256GB. Perhaps its a Virtual memory issue?

Any ideas?

Thanks in advance,
Mia

[Nejc Kilar]

Howdy!

You can see on that screenshot of yours that you're running out of your system memory (RAM) and because of it things that should be in RAM start getting offloaded to your SSD. Even with the fastest SSDs you can buy you'd still be order of magnitude slower than if everything could be properly loaded into your RAM. Basically Corona needs to go search for whatever it needs to do its calculations into a device that is tons slower. The rendering speed in these situations can get drastically lower but on the upside, it'll still render.

As to why your laptop can render it fine with the same amount of RAM I would guess is because you have less memory intensive applications open in the background (like for example post-production tools or multiple 3ds Max instances etc...). Can't say for sure though.

As you noted yourself, a faster GPU will not help you much in this situation as pretty much the only thing a GPU does in Corona is denoising (in the IR or if you have the Nvidia AI denoiser selected).

What I would suggest doing is to either try simplifying your scene so that it fits into your 32GB (and see if it renders appropriately faster) or look into buying more memory.

Hope that helps!

[miacreed]

Hi Nejc! Thanks for your quick response.

Yes, after looking it over it seems that lack of RAM is the issue. My ssd disk is also at capacity- my laptop has 2TB of ssd disk space, so I assume that could be why it works more efficiently.

I can't purchase more RAM at the moment, I was wondering what other alternatives there might exist. Perhaps creating more CoronaProxies? Not everything in the scene is proxied. There are a few trees, people from ChaosCosmos and curtains that aren't proxied. Would this perhaps make the scene lighter and improve rendering time?

Mainly because 16 hours is unacceptable for the type of work Im doing, so I need to find a workaround until I can get my hands on more RAM.

Thanks again for your response.
Best,
Mia

[romullus]

Yes, after looking it over it seems that lack of RAM is the issue. My ssd disk is also at capacity- my laptop has 2TB of ssd disk space, so I assume that could be why it works more efficiently.

If the renderer runs out of available RAM and starts using disk, then it's no matter if it's hdd, ssd, or punch cards - the render will be so unbearably slow that the only viable option is to stop it and look for a way to optimize the scene, so that it would fit into available RAM.

Regarding scene optimization, proxies won't help here, since they use the same amount of RAM like regular geometry. If you need to lower RAM usage, remove all unnecessary render elements, remove lightmix if you can, lower displacement settings (increase screen pixel size), reduce textures resolution and so on.

[miacreed]

Thanks everyone for your responses. It really get a better understanding of how the software works. The scene really couldn't be more simplified, it was already missing trees and a few other atmospheric elements- I finally noticed that the output image size was a bit too ambitious and I cut the size in half, all cores are now at full capacity and the estimated remaining time for the entire render is 45 minutes.

Moral of the story, dont be stingy when it comes to buying enough ram :)
Thanks for the guidance!!!
Best, Mia

[Nejc Kilar]

Glad you got it working and yeah, buying more RAM is typically a good idea as once you start running out of it... Its trouble time! :) Happy rendering!