Long story short: Firefox is just slow. It's tracing engine doesn't cope with heavily branching code like that in an emulator, and it just falls back to interpr

Long story short: Firefox is just slow. It's tracing engine doesn't cope with heavily branching code like that in an emulator, and it just falls back to interpreting it. It's nothing to do with the canvas. (In fact, Chrome's canvas is far slower than Firefox's.) Chrome is wildly fast because it compiles everything to machine code instead of JIT compilation.