Where do I turn off usd preview surface in Solaris?

The materials button also turn off the materials in the render.

It's so annoying having to wait for the textures to load, and see all the VRAM getting lost for something I don't want to see :/

RMB on the material button, then deselect "Textures". This is also available in the Material tab of the Display Options dialog.

It would be great if Karma and OpenGL/Vulkan could remember the 'display materials on objects' checkbox independently.
That way, when switching to OpenGL/vulkan, the textures would stay unloaded. Independent material view control per renderer would be ideal.
Like Heileif said, this would also save a significant amount of VRAM, which is literally wasted.
99.999% of the time, I don't need to see material previews, grey, ugly geo FTW
Hiding textures and setting the draw mode to 'Bounding Box' saves 90% of Vram in heavy scenes.

Antti1999
It would be great if Karma and OpenGL/Vulkan could remember the 'display materials on objects' checkbox independently.
That way, when switching to OpenGL/vulkan, the textures would stay unloaded. Independent material view control per renderer would be ideal.
Like Heileif said, this would also save a significant amount of VRAM, which is literally wasted.
99.999% of the time, I don't need to see material previews, grey, ugly geo FTW
Hiding textures and setting the draw mode to 'Bounding Box' saves 90% of Vram in heavy scenes.

RFE this!

Antti1999
It would be great if Karma and OpenGL/Vulkan could remember the 'display materials on objects' checkbox independently.
That way, when switching to OpenGL/vulkan, the textures would stay unloaded. Independent material view control per renderer would be ideal.
Like Heileif said, this would also save a significant amount of VRAM, which is literally wasted.
99.999% of the time, I don't need to see material previews, grey, ugly geo FTW
Hiding textures and setting the draw mode to 'Bounding Box' saves 90% of Vram in heavy scenes.

This!

quick post to add a +1 on this RFE