>ASM is only 2x slower than native
Only in wilfully misleading benchmarks. Allow use of SIMD and multithreading and asm.js can be as much as 50 times slower:
http://cdn.arstechnica.net/wp-content/uploads/2013/05/native...
http://cdn.arstechnica.net/wp-content/uploads/2013/05/classi...