I would have assumed it was due to a full lobby, but i later then joined in alone and recorded frame timings here - https://gyazo.com/f36c35b977757d1e4b466ad16a5b475e EDIT - A friend that i talked to briefly about shader's said that he is certain the portals use grab-pass distortion to simulate the effect that they use around the rims. This further causes the frame timings to have problems from what i understand. This could be fixed by a possible conversion of the portals shader or a complete redesign overall.