GPU usage when rendering

I’m using a PC with an NVidia GTX 1050 Ti 8Gb card.
The CPU is i5 with 16Gb RAM.

My renders are really slow and I don’t think they should be. I noticed the GPU when rendering only gets to about 6% usage - I would have expected much higher.

For a simple scene at 1920x1080, 256 samples, 64px tile size (bigger seems to slow it down even though I thought it was meant to be the opposite for GPU). it’s taking around 3 mins to render.

What would cause the GPU not to be fully utilised?


according to what?
Windows Task menager with field set to CUDA?

Ooh, ok, I didn’t realise there were different fields! Yup, setting to CUDA in task manager and it now shows as 100% :man_facepalming: Thanks @gorion103

But it’s still slower than I would exepect for that amount of memory on both GPU and CPU. Is there something obvious that I haven’t enabled/disabled that I could check. I know render speed is dependant on many factors though.

What have you set under Preferences -> System?

Just selected the GPU under CUDA and left the rest as default:

I tried selecting both GPU and CPU too.

Ok, that should work. Could you share the render file and the exact render times for CPU and GPU to compare it to my setup (i5, GTX 1660 Ti, 16Gb RAM)

Tube_logo_foil.blend (1.2 MB)

Hopefully that is the file attached. It took 2m 47s with the settings saved.


I rendered it on my laptop and the scene took me 1min 16sec with an GTX 1660 TI 6GB VRAM without changing anything.
In your initial post you said something about a tile size of 64x64. When I opened the file it was using the “Auto Tile Size” Addon (Blender Manual) setup in a way that the tile size was 240x216. I don’t now if you have set it this way or if the Addon automatically did this.
I experimented a bit with tile sizes and using CPU (i5-9300H) and GPU together and I got the fastest render (1min 15sec) with the following setup: Enabled CPU and GPU in Preferences -> System and used a tile size of 64x64

About 1min seems ok for this scene. It is strange that it takes about twice as long on your system. There are only two reasons I can think of why this is happening: How much VRAM does your GTX 1050 TI have? And use some sort of hardware monitoring program to check if your system is thermal throttling.

Btw. nice scene

1 Like

Thanks for doing this.

See that’s what sort of time I was expecting. I wasn’t aware of having the also tile size add-on so I’ll look into that. The gtx has 8Gb ram which I thought was decent (is that what you meant by vram, v being video or is there a virtual ram setting somewhere like you get in Photoshop?). The CPU 16Gb.

You lost me here: [quote=“Patrick, post:8, topic:1237367”]
use some sort of hardware monitoring program to check if your system is thermal throttling.

The scene is a work in progress thanks, still to add texture to the inside of the tubes though and add some creases to the top :slight_smile:

Are you sure about that? Have you used GPU-z to see the specs of that card?
I do not know 1050 Ti versions with more than 4GB of vRAM.

Your render times are fine. Your card is somewhat faster than mine (GTX 960 4GB):

GTX 1050 Ti: 739,703
GTX 960: 838,249

My card rendered that scene in about 3:40 min. I’m not sure about your concern about vRAM. As long as the scene fit in vRAM capacity of your card, render time does not depend on amount of vRAM used. Blender with that scene that you share only uses 450MB vRAM on my machine. You always use an external program to monitor vRAM usage, like GPU-z.

oh, you are right - it only has 4Gb. I don’t know where I saw 8!

I used dxdiag to see the specs

Well, at least it was because of your own misunderstanding and not because of an unscrupulous salesperson who lied to you. The latter would have hurt more.

1 Like

Thanks for the info. I just assumed more vram meant faster renders.

I was using this scene to test the settings and render times but the real issue I’m having is another scene where I’m rendering an animation. Each frame took ~1m40 on the laptop I had from work which had an RTX card (not sure which one - could it have had 16Gb VRAM?), and on this machine, it’s taking 20 min per frame which isn’t workable! Unfortunately I don’t have the work laptop as my contract with them ended.

I also did some tests with a virtual workstation. They have 8Gb VRAM and a ton of RAM. (they have three options - 4 cores - 30.5GB RAM - 8GB GPU; 16 cores - 122GB RAM - 8GB GPU; 32 cores - 244GB RAM - 2 x 8GB GPU)
I tried the first two but still wasn’t as fast as the workstation I used to have and the scene above rendered in 1m 53s which is slower than @Patrick 's test!

You look for render time comparisons in the link I shared above. GTX 1660 Ti is twice as fast as 1050 Ti

I must have read the specs last week without my glasses on! Just noticed it’s an i3 not an i5!!
Intel Core i5-8350K - 4GHz - 4 cores - 16 Gb RAM

Seems like I just need to adjust my expectations. Thanks for the tip for GPU-z, I can see how much of the vram is being used now. I’ll check that for the bigger animation scene.

I just updated the NVidia driver to the Studio Driver, but it didn’t seem to make a difference.

Hi, I just rendered your scene on my laptop (i5-9300h, GTX 1650 4GB VRAM, 8GB RAM) and it took 1:59:97. Auto Tile Size was really activated with 240x216. So your render time seems to be ok, even if I didn´t expect the GTX 1650 to be that much faster than the GTX 1050 Ti. :man_shrugging: