I used <a href="http:&#x2F;&#x2F;jsperf.com&#x2F;or-vs-floor&#x2F;2" rel="nofollow">http:&#x2F;&#x2F;jsperf.com&#x2F;or-vs-floor&#x2F;2</a> in Firefox 40.0.3 and it was only 0.37% faster. Was similar in Chrome.