Yep, big time. The latest Rift SDK added depth-aware timewarp though, so if you could stream the depth buffer as well you could get something maybe non-sickening, but full of artifacts (transparent objects aren't even written to the depth buffer; when a nearby object is occluding the background and you peak around it in a warped frame it gets filled in a way that can stand out; specular highlights are all wrong wrong in warped frames; lossy compression of the depth buffer for streaming would cause glitching on the silhouettes of objects).