Charles Ling adds a comparison to Chrome’s V8 engine as well:
- WebKit SquirrelFish Extreme: 864.1 ms
- Google V8: 1174.1 ms
- Mozilla TraceMonkey: 1334.6 ms
The results above are for the Sunspider benchmark, the Dromaeo benchmark shows similar results. But be aware that some of the speed improvements are only for the most common cases:
So if your particular application uses some uncommon operations it might be a bit slower. The JIT compiler also has some x86 32-bit only optimizations, but I expect these will be ported to other architectures soon.