Suprisingly poor JavaScript performance

It was an unpleasant surprise to see results of Javascript performance for Firefox 3.5.6 running under openSUSE 11.2 64bit. Running SunSpider JavaScript benchmark (SunSpider JavaScript Benchmark) took 4808 ms. One would expect that running the same test for IE8, FF 3.6 and Google Chrome 4.0.249 under XP in VirtualBox would yield somewhat close results. According to Firefox 3.6 performance JS performance of FF 3.6 is about 16% than FF 3.5, so considering VirtualBox overhead, the results should be somewhat close, I thought.

FF 3.5.6 under openSUSE 11.2 64bit: 4808ms
FF 3.6 under Win XP inside VB: 1321ms
Chrome 4.0 under Win XP inside VB: 715ms
IE8 under Win XP inside VB: 8348ms

Are there any reasons when FF would be so much slower? Maybe it is not optimized to work with 64bit OS?

Does anyone have any ideas how to improve it?

Firefox for Linux is much slower than Windows version. I red that Firefox run under WINE is faster. That’s sad :frowning:

You can check Chrome/Chromium or Opera.

Yes, you are right. It looks like it is known problem and when I tested Chromium, I got similar results:

Chrome 4.0.303 openSUSE 11.2 64bit: 1401ms
Chrome 4.0.249 32bit XP in VB: 751ms

Performance of Opera was similar (7219ms vs 4992ms).

I would expect that running browsers in the virtual environment on the same system would cause a performance overhead, but this is not the case.

Maybe it is somehow related to 64bit vs 32bit versions?