I'm putting this here instead of in the Bugs section because the issue may just be that I misunderstand how the 'low quality' fullscreen scaling option works.
Basically, 'low quality' fullscreen scaling is supposed to render the game at a specific size, then stretch it up to the window size. This has the side effect of the game looking blurry if the screen is too big, however it's very necessary if the game is bottlenecked by GPU fillrate.
Now, my expectation is that, once low quality fullscreen scaling is set, the actual window size should have no effect on performance. However, recently I've been noticing that the opposite is true - having a bigger window size is more costly, even when low quality fullscreen scaling is on.
This happens in all browers I tested - Chrome, Canary, Node-Webkit, Internet Explorer, and Firefox.
I've attached a capx so you can test it for yourself. Instructions are included in the event sheet.
I really, really hope this is a bug, but I can't be sure. Am I just fundamentally misunderstanding something here? Or is there really a problem with C2's implementation of low quality fullscreen scaling?