I don’t know enough about Xenos architecture to comment on that, but for R600 vertex fetch could be used for texture point sampling. I don’t think I’ve seen it referred to as a point sample texture unit in any official presentations though (not that it would surprise me if it did). Using Vfetch for texture sampling requires that the texture is stored in a linear format rather than swizzled. This isn’t something the application has control over on the PC, unlike the XBox360, so the driver would have to somehow figure out that a certain texture should be stored in a linear format to allow vfetching it.