GPU memory usage

[BorisGoreta]

Why is 1.1 GB of GPU RAM immediately unavailabe when I start rendering ?
I am using a dedicated display card and not rendering on it.

[BorisGoreta]

Other computer has 281.4 MB unavailable on the same scene.

I am thinking this is display memory since this other computer runs at low resolution and the first one was running 2x 2560x1600 monitors.

But I thought that if you had a dedicated display card the other cards can use full 6 GB of GPU RAM.


Also what is the deal with nodes ? Is it possible to disable display altogether so all GPUs can use full RAM. I don't have dedicated display in the nodes so I am thinking on how to maximize GPU memory there. Currently I have unplugged display cables from there hoping this would release the display RAM but I am not so sure it works that way since this node has 281.4 MB unavailable. Is there a way to free more RAM and how ? Should I lower the display resolution to minimum ? Having all 6GB free without a dedicated display card impossible ?

[grimm]

Are you changing the image resolution between the two? Your final image will take vram to store before it gets moved back to your system ram. It looks like this is one of the things the devs are planning to fix in the 3.0 release. Yay

[BorisGoreta]

Image size is pretty much the same. The one that loses 1.1 GB is Win 10 and the node is Win 8.1

[grimm]

The Blender users over at BlenderArtists have noticed the same thing with Cycles. I'm wondering if it has something to do with CUDA or the driver. Have you updated your drivers lately? When I get home tonight I will run some tests and see if I can see anything. Very strange.

[BorisGoreta]

I have lowered screen resolution from 2560*1600 on 2 monitors to 1280*800 on a single monitor and still 1GB is used which proves that this is not an issue with the display. Who ate 1GB of GPU RAM !?!

[grimm]

I have no clue as to what is going on, I have the same issue but not as bad. I played around with the number of polys and textures but the unavailable memory didn't change much.

The Nvidia X-Server tool agrees with what Octane is reporting, but I don't know why Octane takes that memory (buffer?). The 980 is not connected to any monitors, the 460 drives my displays. If I quit Octane the Nvidia tool reports that just 15 Mbytes is being used, so Octane did pull that unusable memory.

[BorisGoreta]

What is this monitoring software you're using ?

273 MB sounds about right for display but 980 should be completely free.

[grimm]

It's a program that comes with the Nvidia drivers for Linux/Unix.

I would be fine with the memory being used for the Octane kernel code, but yours is so much larger that it doesn't make sense. You would think that it would be a similar size if that was the case? Unless there is something else going on that I don't understand (which is probably the case ).