[gsnedders]

But given most JS code in the real-world is mostly dominated by DOM performance, and not JS engine performance. Certainly JSC's llint gives it a substantial benefit over V8 on cold code, but I'd be surprised if it accounted for even the majority of the battery life gain. I'm not questioning Safari's lead here, just how it's so much better. (I think the lead is clear, with perhaps only Edge getting close, but that's hard to compare.)

[om2]

Like I said, the JS engine is likely not the main factor. But it does make a difference. I don't have a detailed breakdown to share but we do measure these things. :-) The prior poster was wrong to imply it's all down to the JS engine, but swapping WebKit for Blink would very likely hurt our battery life.

Windows itself has worse battery life than OS X on identical hardware, so it's hard to compare Mac browsers to Windows browsers. Safari on OS X is the best laptop browsing power efficiency you can get, and likely the best battery life barring laptops with super huge batteries.