skelooth , I don't know how to check if it's reported incorrectly, I am able to run very complex scenes with tons of webgl effects in constant 60 fps and the jerkiness will be the same. If my card is somehow blacklisted and my tests run on brute force with a handicap that takes the form of stuttering, I would very much like to know how to check and fix it, although the same will hold true to any other user that will try to play the game and will be vulnerable and hopeless against the Browser's capricious blacklisting. Also, if this isn't the case, I wonder what good is disabling webgl in C2 is for, if it creates this kind of fundamental problem. I don't think that's the case.
On the other hand, contrary to the issue mentioned in this post , I don't encounter these crippling problems that are mentioned there when the frame rate goes below any reasonable value. I made a test that spawns sprites until any given fps threshold and up to 17.000 sprites or so I get 60 fps. If I continue to spawn sprites the game still feels ok until 20-25 fps (around 27.500 sprites), at that time it just doesn't feel responsive anymore. The jerkiness issue that I have exists in every intermediate frame rate value, but when the fps drop as low as 20 or so it's not anymore a noticeable or relative issue.
Also, in your last post if you are referring to Colludium , he has Intel HD graphics, I am the one that mentioned the 660 ti.
Colludium , are you sure that you can't detect the issue after 10-15 seconds? Remember that it comes and goes sporadically and it's evident if you keep following the square with your eyes (in my example). Otherwise, you need to have some kind of interactivity to notice it (like a platformer that moves and jumps around), or infinite scrolling backgrounds that move at constant rates.
And yes, I feel too that changes in scenery (like moving into an other area of the layout) affect this issue. I just don't even go that much ahead, I want to nail it and see if it exists even at the basic level.