http://en.wikipedia.org/wiki/General_Electric_GENX

Fuel burn reduction technologies include;

* Fan bypass ratio of 9.5:1 which also reduces noise
* High pressure compressor based on GE90-94B with 23:1 pressure ratio
* Counter-rotating spools (first employed by Rolls-Royce Trent 8104)
* Combustors with improved internal airflows which also reduces environmentally-harmful emissions