Ok, I have a procedural voxel terrain generator which works perfectly fine, I get around 50-60fps. But I was wondering if having no textures (for things like: grass,stone,brick) and having colours instead would increase performance. I hope one of you smarties knows
Yes, but only if you substitute your current shader that takes a texture with a faster shader that does not. A vertex-colored shader with fake lighting can be extremely fast, especially if you combine all the meshes that use that material into one big mesh.
However to get it to look as good as the textured version, you are going to have to greatly increase the vertex count of the building blocks, and there is your tradeoff.
Realistically the speed difference will be minimal at best; certainly not measurable in terms of FPS. Drawing textures is not something that graphics cards have a problem with.