I don't agree with that interpretation of the data. If you are peaking at 100% for less than 5 ms, that is not going to cause stutter like we're seeing it. I've worked as a programmer for more than 20 years, including several those in the games industry and even doing some work on consoles, so I'm quite familiar with the differences between average fps, frame time spikes, etc.



For actual visible stutter you need a far longer spike of 100%, and even then it's not proof of a being limited by single-core performance - as it's perfectly possible to structure the engine architecture in such a way that the render-loop is not blocked by the simulation-loop blocking for one or more frames.



To me this looks much more like the characteristics of one or more synchronization bugs/issues. It could be an architectural problem, but hopefully it is less serious. Listening to and looking at the tech lead during the stream did give me a feeling that there is a least some technical debt and/or architectural work of a painful nature, standing in the way of a (relatively) quick fix.



If I find the time I'll fire up PerfView and get some detailed data to back up my claims.