Whenever the issue of Firefox's performance or resource usage comes up, the response is usually along the lines of, "There are no problems."
Then somebody usually links to http://arewefastyet.com/, using it as "evidence" that Firefox is somehow faster than the competition.
Meanwhile, there are many of us sitting here using Firefox, suffering from the poor performance that was initially inquired about, wondering how it could possibly be claimed that such an obvious problem "does not exist".
... which is understood polite-speak for "Yes, it's a problem. No, nobody is volunteering to fix it right now."
This behavior people have been railing against for years is once again standard.
In fact, this uses threejs[1] under the hood. It is just that the version of Firefox someone is using sucks in comparison to Chrome for the three.js stuff (likely WebGL).
Now, maybe there's a greater chance that the situation will change, and other suitable implementations will eventually arise. But until that happens, an open standard with one usable implementation really isn't different from a closed standard at all.
However, Khronos[1], the entity that makes opengl, also made the webgl standard. The fact that mozilla hasn't done as good of a job implementing it as google has doesn't magically negate the fact that it is still an open standard (that mozilla has actually implemented, just poorly).
My personal favorite bug: [https://bugzilla.mozilla.org/show_bug.cgi?id=116083]
Long story short: "It'll be a problem until someone patches a solution in."