This is really a duplicate of the question- link text
I googled it and found some old results like bubblemark.com, link text and link text. But is there any recent benchmarks as all the platforms have been updated. I like to measure the speed of silverlight 4 against the modern and faster javascript engines. Anyone have any source?
I haven't found too much for new raw JavaScript engine numbers or for Silverlight, but along those lines are some benchmarks of HTML5 verse Flash if that helps you at all. Of course it takes into account rendering performance rather than just pure computational performance:
http://themaninblue.com/writing/perspective/2010/03/22/
there is also a video showing the tests being performed on mobile devices http://vimeo.com/10553088
Certainly JavaScript engines have made up a lot of ground. Google's V8 engine added a JIT compiler which was much needed and helps reduce the performance hit of being dynamically typed.
While I don't have sources atm to back this up I suspect that for raw speed it is Silverlight > Flash > JavaScript. Of course in applications the biggest bottlneck is the rendering which is why IE9's GPU rendering has seen some massive speed increases in some tests. This can also be seen in Flash with Joa Ebert's Java+OpenGL implementation of the Flash Player showing big increases in some areas. http://blog.joa-ebert.com/2010/08/19/introducing-jitb/