Blender Cycles "Out of memory" when it reach 2 GB with the GTX 980 4GB

Most of everything is in the title, i have a Gtx 980, which has 4 GB of memory, but i can’t use more than 2GB.
What’s the problem ?
Here is my system spec :
-Windows 10 Pro 64bit (either with 8.1 i’ve got the problem)
-GTX 980 4Gb MSI gaming edition
-FX 8320 CPU
-8GB of ram
-SSD + Hard Disk (128 + 2TO)

Well, so i have a question too : can i store all the memory supposed to be in VRAM in a SDD for exemple ?

Thanks in advance,

MagicalPaladin

Hi, how do you measure this, do you have an example file?
I have a 4 GB card too and can test.
2. Most OS already have a Ram disk, if you run out of memory it stores some data on the disk.
Make sure your OS use the SSD for this.
You can create a RAM disk for your system too, search for RAM disk, it depends on your OS.

Cheers, mib

Hi,

Thanks for the answer, here is a screenshot



and here is a file :
https://drive.google.com/file/d/0BxXIPxgW1LkZMTZ5VEhRdlpnNEE/view?usp=sharing
how a ram disk can handle Vram data ?

thanks,

MagicalPaladin

That information that shows Blender is not the real vRAM usage by all CUDA. You use GPU-z or a similar program for monitoring the vRAM (nvidia-settings in Linux)
https://developer.blender.org/T43310

I know, but it renders nicely on the cpu (much longer but working)
and i have GPU-z installed, i have not figured any problems, the memory doesn’t reach 3.5GB.

My system (Linux) uses 300MB vRAM with Blender opened. When I run the render with your file, vRAM reach a peak 3257MB. So you check with GPU-z the vRAM usage by your sistem with Blender opened, but before executing the render. How is the amount of vRAM that indicates GPU-z in those conditions?

Edit:
Surely it works well with CPU because you have 8GB of RAM + virtual memory on disk. GPU render uses the vRAM only.

550 MB precisely

why the 2 subD mods?? and no file for the displace (why is that a hdri)

There is two sub to have more than 6 subivision levels.
the Hdri is an addon, don’t need to use it.

I don’t know, perhaps for some reason render in Windows use a little more vRAM than in Linux, and that is enough to complete the 4GB vRAM your card.
Regarding SSD. I read that the memory cells in ssd have a certain lifespan where it start to deteriorate when reach certain cycle of use. I did not know about the RAM disk that mib2berlin mentioned. But you should investigate whether to make such use of SSD (or use the virtual memory in the ssd) it could shorten much the life of the SSD.

that’s really weird, i will look on a “out of core” render compatible with Blender when i’ll have some free times, or a way to increase that memory size.

i have increase my virtual memory (the one windows use to store temp files), it stopped less than 2GB, i will run a render when i can.