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JohnG
10-08-2012, 02:05 PM
So I start a render on the GPU in the background, Move uses 1.6 GB of VRAM of the 4 GB available on the GPU.

However the OfflineRenderer process uses 3.9GB of system RAM, is this normal and why does it need so much ?

Also given that Move is set to use just one GPU for rendering (a 4GB GTX 670) why does it grab over 700mb of VRAM from the other GPU?

If I close Move while the background render is taking place it releases the 700MB of memory from the second GPU. The scene I was rendering had around 5.7 million polys and the render was 4K.

andy
10-08-2012, 02:59 PM
Some of that makes sense. You don't have quite as much control over what GPU you are using for the GTX series, so feel lucky that you can even limit which renders. As one is rendering, all other programs will switch to using the other because windows handles that right? So that explains the 700mb of vram changing, and even releasing after you close Move.

The 3.9GB of system ram is most likely cache for the scene. The system needs memory to be able to write information to files, like the image file, as well as other info. You have to be able to load the whole scene on your VRAM, but it can still write other information back and forth between ram. I notice the same sort of hit on iRay using 3dsMax as well. A coworker is also using VrayRT and it uses a ton of memory, granted that is using OpenCL so uses the processor for Everything that isn't brute force calculations.

As far as I know, it seems everything you listed is normal behavior.

JohnG
10-08-2012, 04:17 PM
Yes you're probably right about the system ram, its good to know that other rendering applications are just as memory intensive.
Although I still don't see why Move should use so much VRAM from the GPU used for the display, sometimes it maxes it out which can slow down other programs such as the Bridge or Photoshop.