Sun spider extremely slow on Safari

[Razer(x)]

I've tried Sunspider on Yosemite and it takes forever to finish

No problems with Firefox

You can check yourself
https://www.webkit.org/perf/sunspider/sunspider.html

I've already reported feedback to Apple

 

[simon48]

Safari is 13ms faster then Firefox for me. 137ms vs 150ms. I bet it's on your end, have you tried restarting?