Some additional data about Emscripten code without asm.js mode, corresponding to memory model 2 in your comment. We generated the data on spidermonkey using the --no-asmjs command line switch.

Startup time: https://docs.google.com/spreadsheets/d/17fFM1YqhMV2-O0ZdymEv...

Execution time (small benchmarks): https://docs.google.com/spreadsheets/d/17fFM1YqhMV2-O0ZdymEv...

Execution time (larger benchmarks): https://docs.google.com/spreadsheets/d/17fFM1YqhMV2-O0ZdymEv...