From the Blender manual:
“With CUDA and OptiX devices, if the GPU memory is full Blender will automatically try to use system memory. This has a performance impact, but will usually still result in a faster render than using CPU rendering.”
Does this mean that unless we max out the gpu + system memory there won’t be any out of memory errors anymore?
I did some tests in 2.9, with high resolution 16 bit textures, using GPU Optix rendering, on a RTX super with 8gb of ram.
I did not see a significant performance drop in rendering high res textures when staying within the GPU memory limit (7’767mb of ram) or exceeding it (14’561mb of ram) thus requiring the system memory to kick in.
I can also render highly subdivided meshes with an 18gb memory usage, using the GPU and Optix:
So what are the actual limitations of exceeding the GPU memory limit, since Blender then relies on the system memory? Is the performance drop high enough to justify spending that much more on higher VRAM cards?