Render with Cpu or gpu?

riomai

Hello to all.

Sorry for the question but I'm newbie... Why when I'm going to render my pc use only the cpu and very little the gpu?  It's normal?

Thanks

Richard Haseltine

The default display in Task Manager does not catch Iray activity - if you go to the perfomance tab (you will need to turn on details to see the tabs) and change one of the graphs to CUDA (or, if that isn't an available option, Comput 0) then you should see the activity. If it really isn't using the GPU when you look there then it could be the driver version you are using, or it could simply be that it ran out of memory and dropped to CPU. What CPU are you using, and what did you have in your scene?

riomai

Thanks Richard as always. Just a naked character in pose... with a gtx 1060 3gb (a 1060 do not offend me)

riomai

... Ops sorry... Cpu?! A ryzen 9 5900x

DrunkMonkeyProductions

To add to richard's points.

Check if you have, under devices, in the Render Settings(tab)>Advanced(top of the tab, right of editor), the gpu is available, and checked, and if the cpu is checked and also check if you have "Allow cpu fallback" checked.

If you uncheck both, cpu options, it won't use the cpu for rendering.

Even if a gpu is listed, it doesn't always mean it's compatible and will be used. Maxwell gpus(deprecated) and up are required for gpu rendering in 4.15 and above.

If you're not on windows 10, you won't have an option for "Cuda" under the task manager. There are also some gpus that aren't supported by the task manager.

In that case, either GPU-Z or Nvidia-SMI, will allow you to monitor gpu usage.

Gpu-z is a third party program you'll need to download from their site to use.

SMI is a command line tool included in, most, driver packages for nvidia cards. It'll be in the Program files>Nvidia corporation>NVSMI, by default.

 

Richard Haseltine

I don''t think you will be able to use a 3GB, non-RTX card for much. as I understand it some of that memory is going to be taken to emulate the RTX features, and a 3GB has always been marginal for Iray.

riomai

Thanks you both.

Which video card would you recommend me? I'm thinking about the 3060 12 gb (those above the 3060 seem to cost too much for me and have less gb) ... in your opinion?

Thanks

Richard Haseltine

That should be a good pick - but note that in order to have enough workspace to feed the GPU you will probably want at least 24GB of RAM (of coruse you probably won't jump to doing scenes that max out the 12GB card immediately, so that may be a phased update if you are currently on a lower amount of RAM).

kyoto kid

...another good monitoring tool for GPU performance is MSI Afterburner (free and works with any make of Nvida GPU).

 

Matt_Brown

I have recently upgraded to an Nvidia 3060 12Gb card and have found it to be an awesome investment (even at today's inflated prices). Having enough VRAM is the thing that stops your renders head off to your CPU and you have to spend a small fortune to beat the 3060's 12Gb.

kyoto kid

...would like one as well but need to wait for prices to come back down to earth (if they ever do) 760 USD (average price I've seen on eBay) or more is just a bit too rich for the budget. Have notifications set up with a couple manufacturers but feel the odds of hitting 4 out of 6 on the Megabucks Lotto (120$ - 200$) may be better. 

StratDragon

I could sell the GPU I bought in 2019 for 2x what I paid for it, used. The problem is I cant buy anything else once I sell it.

thanks for the tip, Richard. I noticed this the other day with the GPU in task manager and wondered why that was. I ended up using GPU-Z