Out of Core settings can be accessed from the Render Toolbar > Devices Button > Out of Core.
Enabled - When enabled, OctaneRender uses out-of-core data when a scene does not fit in VRAM.
RAM Usage Limit (GB) - Limits how much system memory OctaneRender® uses for out-of-core geometry and textures. Once texture or geometry data is placed on this amount of RAM and the out-of-core feature kicks in, this specific memory is not accessible by the operating system for other tasks.
GPUThe GPU is responsible for displaying graphical elements on a computer display. The GPU plays a key role in the Octane rendering process as the CUDA cores are utilized during the rendering process. Headroom (MB) - Specifies the amount of space reserved for other GPU users. OctaneRender® maximizes the amount of memory up to the headroom limit specified here. VRAM is faster than RAM, therefore GPU Head Room tends to be set to a minimal level since it is practical to have the maximum amount of texture and geometry data fitted into VRAM.
Apply Out of Core Settings - This button must be pressed to apply the changes made in Out of Core settings.
The out-of-core feature lets you use more textures and geometry than would fit in VRAM by keeping them in RAM instead. The data for rendering the scene needs to go to the GPU while rendering, so some tradeoff in the rendering speed is expected. This also means that as the CPU accommodates requests to access the host memory, CPU usage increases, and any RAM occupied with out-of-core data isn't available to other applications. This holds true also for the slave nodes if the network rendering feature is deployed. If out-of-core textures are not used, the rendering speed is not affected.
The out-of-core feature comes with another restriction - out-of-core data must be stored in non-swappable memory, which is limited. When the host memory is used up for out-of-core data, the system cannot make room for other processes. Since out-of-core memory is shared between GPUs, you cannot turn devices on or off while using the out-of-core feature.
When using the out-of-core feature on slave nodes through network rendering, you'll need enough RAM for the slaves. For net render slaves, you can specify the out-of-core memory options during the daemon installation. When specifying this for the slaves, the out-of-core memory amount should be entered in bytes, not gigabytes.
For example, if the master is rendering a large scene that has texture climbing up to 6 GB, the out-of-core memory amount to specify for the slaves during the slave daemon installation would look like this:
octane_slave.exe --net-master-address 192.168.xxx.xxx --net-master-port 21000 --out-of-core 6442450944
With the added support for out-of-core geometry in OctaneRender®, you can use a significant portion of the system memory for geometry data. You can utilize multiple GPUs in conjunction with the out-of-core feature.