All you are doing is comparing Javascript to SC. One is highly optimized and often JIT compiled (or AOT compiled), the other is a scripting language made by one dude on top of an already slow compiled language. What a pointless comparison, the only thing more pointless would be comparing C to Ruby, finding Ruby is slower, then saying C is better in every way because its faster--I have actually seen a person do this.
Also, if I am not mistaken, all your "speed-test" does is update a variable hundreds of thousands of times. So all you are testing is variable allocation. The single most unfair thing to test between compiled and interpreted languages. Not to mention completely worthless in an real life scenario. Do something intense, like a program that calculates the n-body problem, or constructs a big binary search tree, then searches it. In addition a more meaningful and interesting comparison would be HTML5 GM vs raw javascript, so you can see how much, or little, performance is lost as an overhead for using the GM.