All tests were performed using a Pentium 4 "Northwood" CPU with 1GB of DDR333 RAM running Windows XP Professional SP3. This system is not representative of modern hardware. In particular I would have liked to test using a system with multiple CPU cores. It should be noted, though, that browser performance is particularly important on older, slower hardware, of which this system is representative.
The list of "current version" browsers tested:
1. Safari 3.2.1 (525.27.1), released 11/24/2008
2. Firefox 3.0.5, released 12/16/2008
3. Opera 9.63 (build 10476), released 12/16/2008
4. Chrome 184.108.40.206, released 1/9/2009
5. Internet Explorer 7.0.5730.13, released 10/18/2006
The list of "bleeding edge" browsers tested:
1. Webkit (i.e. Safari) r39731, built 1/9/2009
2. Firefox 3.2a1pre, built 1/9/2009
3. Opera 10.0 Alpha 1229, built 1/13/2009
4. Chrome 220.127.116.11, released 1/8/2009
5. Internet Explorer 8.0.6001.18241 (Beta 2), released 8/27/2008
And the executive summary:
1. Opera is outclassed pretty much everywhere. It does especially poorly on SunSpider. While 10.0 does improve on 9.63's performance, it's not the quantum leap we see with the other browsers. Note, though, that it still beats IE by a huge margin.
2. Chrome loves it some Dromaeo. In the "bleeding edge" category Chrome is 2.5x as fast as its closest competitor, while in the "currently released" category it's about 6x as fast. It performs well on SunSpider too, but the difference isn't as stark.
3. Chrome 1.0 performs about as well as Chrome 2.0. I'm pretty sure this can be attributed to Google's release model, in which even the "current release" is fairly bleeding edge.
4. In the "currently released" category Chrome is the hands down winner, with FireFox and Safari in a statistical dead heat at a distant second. Of the two, Firefox appears to have a slight edge, though it really depends on the benchmark. Opera comes next, with IE7 way, way, way out in last place. See #6 below.
5. In the "bleeding edge" category the situation is more interesting, mostly due to Chrome's freakishly good Dromaeo performance. While Chrome and Webkit are the clear leaders, sporting almost identical Sunspider scores, Chrome enjoys a huge lead on Dromaeo. FireFox trails both Chrome and Webkit, then comes Opera, then IE8 pretty far out in last place.
6. While IE7 is categorically slower than all competitors, its SunSipder numbers are exagerrated due to its pathologically poor performance on the" base64" and "validate-input" tests, and to a lesser extent on the "tagcloud" test. Even with those tests removed, though, it is still approximately 3x as slow as Opera, which is the slowest of the "currently released" non-IE browsers.
7. IE8 corrects the pathologically poor IE7 performance on SunSpider's "String" benchmarks. It also makes incremental gains on the rest of SunSpider. That said, it is still outperformed across the board by even the slowest of the "currently released" browsers, Opera 9.63.
8. Neither IE7 or IE8 is able to finish the Dromaeo suite. Both fail on the "base64" section. On the "Arrays" section, which precedes "base64", IE7 scored 48 runs/sec and IE8 scored 142 runs/sec. By contest, Opera 9.63, which had the lowest score of the non-IE browsers on the "Array" section, scored 168 runs/sec.
Here are the actual scores, in case anyone cares to do a more fine-grained analysis. Remember that for Sunspider lower is better while for Dromaeo higher is better:
IE 8 Beta 2: S: 17389, D: failed