Since the Penelope EA launch, I made no updates on anything, because, well, too dangerous. I stayed with r186.2 for months.
I was curious about the last C2 update because of the perf improvements, and just tried the game on a quite low perf laptop.
C2 r196 + Chrome Version 40.0.2214.94 m:
I get a few janks on start (music loading I guess), then, YEAH BUTTERSMOOTH YEAH.
The game was running at 40/45fps max before on this hardware + chrome, and it's now 60fps with all effects enabled, rock solid.
Particles, destroy events, and shaders seems do not harm the framerate anymore. Create events can cause a few janks, but subtle ones, nothing important.
Lovely surprise, oh, and frameskip seems way more visualy correct as well.
So, thanks a lot Ashley, I don't know what changes had the more impact on the game, but it seems to be for the very best! : )