I compared it casually with the original JavaScript implementation: in both Firefox and Chrome, both JS and WASM hit max FPS easily (165, in my case, incidentally). According to Firefox’s profiler, the JS version experiences noticeably more frequent jank; Chrome’s profiler doesn’t obviously show any jank for either. In Firefox, both are around 50% idle and there’s no obvious difference in their performance, though they definitely have different hot spots. In Chromium, indications suggest the WASM is being a few percent more efficient, spending 68–70% idle versus JS’s 65–66%; it spends much less time in scripting (~17% vs. ~22–23%), but more in rendering, painting and “system” (whatever that is) which make up the balance of that 100%.

These results are utterly unscientific. You also can’t compare Firefox and Chrome’s profiling numbers to one another.