SunSpider is about one thing and one thing only — cold code performance. The benchmarks are all so short (the longest in Spartan is 19.7ms, albeit with a large

SunSpider is about one thing and one thing only — cold code performance. The benchmarks are all so short (the longest in Spartan is 19.7ms, albeit with a large uncertainty) that it's all about how quickly you can JIT code and get rid of the dispatch overhead of any interpreter you have, and how many optimizations you can do in that very quick first compilation. If you're interested in longer running code, where implementation quality makes a far bigger difference, look at Octane and Kraken. Chakra, Spartan's JS engine, has long been good on SunSpider.