Recently, I've [bitterly complained](this-is-the-end-of-opera.html) about the mediocre performance of Opera on sites making heavy use of Javascript. As if they'd heard my complaints, [Opera labs](http://labs.opera.com/news/2009/12/22/) today released a pre-alpha of the forthcoming Opera 10.50, including the new Javascript engine Carakan which is finally using [JIT](http://en.wikipedia.org/wiki/Just-in-time_compilation). Since the Unix version hasn't been released yet, I did all tests under Windows 7 in Virtualbox:

Safari 4.0.4 531.21.10	Windows 7 64 bit, VirtualBox 3.0.12	578.8 ms +/- 13.7%
Opera 10.50 3172	Windows 7 64 bit, VirtualBox 3.0.12	688.8 ms +/- 6.2%
Opera 10.10 1893	Windows 7 64 bit, VirtualBox 3.0.12	3975.4 ms +/- 2.0%

Not too shabby, I'd say. 😄 All of the above, as usual, on a Core 2 Duo E6600 running Mandriva 2010 x86\_64 as the host system. In this context, I thought it would be interesting to compare these values to those obtained with much faster hardware (namely, a Core i750) running Windows 7 natively.

Safari 4.0.4 531.21.10	Windows 7 64 bit, native	676.0 ms +/- 6.7%
Firefox 3.5.5	Windows 7 64 bit, native	1007.8 ms +/- 5.7%
Opera 10.10 1893	Windows 7 64 bit, native	2957.0 ms +/- 0.4%
IE 8 7100	Windows 7 64 bit, native	4285.4 ms +/- 1.1%

Surprise, surprise. The only browser which scales almost exactly with the more than twofold performance increase per core is Firefox (which took [2274\.8 ms](this-is-the-end-of-opera.html) to complete the test on the E6600). Safari, in contrast, does not scale at all. Quite sobering, isn't it? It will be interesting how future versions of Firefox and Opera will behave in this respect. 😉