Out of curiosity I tried to run the SunSpider JavaScript Benchmark from http://www.webkit.org/perf/sunspider/sunspider.html with the latest N9's Opera Mobile 12.10.1 .

Unfortunately Opera got stuck downloading the 1.3 MB Javascript benchmark blob code wrapped into an HTML page.

Does OM has problems loading huge JS files over the network?

Loading the benchmark HTML page locally as file:/// did work and gave a result of ca. 5000 ms, somehow a little bit worse than the N9's builtin webkit browser (4250 ms). The best performance had Firefox Mobile 14 with less then 4000 ms.
I don't find the difference significant that I would use only one of the browsers and JavaScript performance of course is just one part of the browser's user experience.

Are there some JavaScript performance tweaks in the latest Opera update as on a much slower non-overclocked N900 with a slightly newer OM (12.10.16) I got SunSpider around 6000 ms? Or is this just a matter of the compiler's version and the compilation options?

Best, M.