Firefox 4's JavaScript engine is now faster than V8 (used in Chrome) and Nitro (used in Safari) in the SunSpider benchmark on x86. On Mozilla's test system Nitro completes the benchmark in 369.7 milliseconds, V8 in 356.5 milliseconds, and Firefox 4's TraceMonkey and JaegerMonkey combination in 350.3 milliseconds. Conceivably Tech has a brief rundown of some benchmark figures from their test system obtained with the latest JS preview build of Firefox 4: 'Our AMD Phenom X6-based Dell XPS 7100 PC completed the Sunspider test with the latest Firefox JS (4.0 b8-pre) build in 478.6 ms this morning, while Chrome 8.0.560.0 clocked in at 589.8 ms.' On x86-64 Nitro still has the lead over V8 and TraceMonkey+JaegerMonkey in the SunSpider benchmark.