I imagine that the developers probably have had that Javascript speed test sitting around for awhile, so by nature they would attempt to improve their performan

I imagine that the developers probably have had that Javascript speed test sitting around for awhile, so by nature they would attempt to improve their performance in those tests. Besides which, I feel the amount of effort put into improving Javascript execution speed has been quite little thus far, and so a team quietly plugging away trying to create the fastest implementation could conceivably do far better. All that being said, I'm seeing numbers around 200 on my machine, and really not that much faster in other browsers.