The Textures rollout is accessible through the Perf. tab of the Render Settings. These options give direct UI access to texture-related operations when the renderer is V-Ray GPU.

UI Path: ||Render Setup window|| > Performance tab > Textures rollout (Renderer set to V-Ray GPU)

Mode – Determines how the resolution and size of textures are handled to optimize the memory usage.

Full-size – Textures are loaded at their original size.
Resize – Adjusts the size of high-resolution textures to a smaller resolution to optimize render performance.
On-demand mip-mapped – Instead of loading all the texture files at their default resolution (original or resized), V-Ray GPU loads the textures as needed and automatically creates mip-map tiles for them (regardless of their texture type). As a result, the GPU memory consumption is decreased; textures that are not visible are not loaded, and textures that are further away from the camera are loaded with lower resolution.

Max Size – Specifies the resolution to which textures are resized when Mode is set to Resize.

Format – The amount of bits per channel used to store the material texture information into memory. This does not affect textures used for lights and displacement.

8-bit – 8 bits of data used per color channel.
Half – 16 bits of data used per color channel.
Float – 32 bits of data used per color channel.