Author Topic: IRay randomly decides to not use GPU  (Read 1641 times)

So one thing I've noticed about IRay is that it seems to at times randomly decide to not use the GPU, drastically slowing down the rendering time. I have not found anything in particular that seems to cause it. Even closing and reopening Painter doesn't seem to get it to start using the GPU again.

Are you working on a laptop or a desktop computer ? If the former, and you have not forced Painter to use your Nvidia GPU, it could be that the OS has decided to switch to battery saving mode and run all graphics processes on the integrated graphics hardware rather than on the dedicated GPU.
Last Edit: March 18, 2016, 03:19:27 pm

No, a desktop computer.

I even made sure to set up an application-specific nvidia settings profile that has the power saving mode to "Prefer Maximum Performance"

Sometimes it uses the GPU to great effect (i.e. I can get 55-60 iterations in 20 seconds), sometimes it seems to completely ignore the GPU (and do about 12-15 iterations in 20 seconds).

Is there a minimum amount of VRAM recommended for Iray rendering? According to my output I'm getting a lot of out-of-memory errors on my 2gb card.

I've attached the log where my GPU usage went down to 0% pretty much when doing an Iray. The very last Iray render is the one where it seemed to happen most noticeably.