It may sound counterintuitive, but to get rid of the aliasing artifacs you sometimes get with hi-res hair is reducing the texture size. What happens when rendering hi-res textures on small objects is that one pixel in the rendered image equals multiple pixels in the source texture. The renderer thus skips quite a few pixels in the texture when rendering, which leads to the artifacts you see. When you lower the shading rate, it's taking more texture pixels to create one pixel in the rendered image, which obviously takes a more time. Texture filtering is using a special lookup table to lookup the color of an area of the texture without having to look at each individual pixel in the area - faster, but uses more RAM. But, the best way is to not cure the symptoms but to cure the cause: The discrepancy between texture size and (rendered) object size: A hair prop that takes 300 by 500 pixels in the final image doesn't need a 2048x2048 texture.