OUT OF CORE texture
Out-of-core textures allow users to use more textures than would fit in the graphic memory (VRAM), by keeping them in the host memory (RAM). The data for rendering the scene needs to be sent 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 will increase and any RAM occupied with out-of-core textures will not be available to other applications. This holds true also for the slave nodes if OctaneRender Network Rendering feature is deployed. If out-of-core textures are not used, however, the rendering speed is not affected. Note also that OctaneRender’s Out-of-core settings is only for textures, not geometry or render buffers.
Out-of-core textures comes with another restriction; they must be stored in non-swappable memory which is limited. So when the host memory is used up for out-of-core textures, bad things will happen since the system can not make room for other processes. Since out-of-core memory is shared between GPUs, users also can not turn devices on or off while using out-of-core textures.
OUT OF CORE geometry
Same usage as above but this time it uses CPU Ram for geometry. So, it's allowing you to use a significant portion of your system memory for geometry data. Multiple GPUs are also supported with out of core geometry. In some scenes, the number of geometries may be high and the GPU ram may not be enough for such high geometry scenes. In such cases, "Ram Usage Limit (GB)" can increase and work easily. Of course there will be a minimal slowdown, but this is due to the difference in speed between the GPU ram and the CPU ram. GPU Ram is always faster.
Enable OUT of core textures/geometry:
You can activate or deactivate this feature from here.
RAM USAGE LIMIT(GB):
Here you can adjust the amount of Ram in your system. Remember that the value you enter here will no longer be used by the system.
gpu head room (mb):
Default setting recommended.