A higher bypass pressure ratio (BPR) improves thermodynamic efficiency and also propulsive efficiency.
B777-200ER Engine comparisons:
GE GE90-94B
FAN DIAMETER: 123 Inches
COMPRESSOR LAYOUT: 1 Fan/3LP+10HP
TURBINE LAYOUT: 2HP+6LP
BPR: 8.40
MASS FLOW: 3398lb/s
TO THRUST: 93,700lbt
PRATT-WHITNEY PW4090
FAN DIAMETER: 112 Inches
COMPRESSOR LAYOUT: 1 Fan/6LP+11HP
TURBINE LAYOUT: 2HP+6LP
BPR: 6.41
MASS FLOW: 2948lb/s
TO THRUST: 90,100lbt
ROLLS-ROYCE TRENT 895
FAN DIAMETER: 110 Inches
COMPRESSOR LAYOUT: 1 Fan+8IP+7HP
TURBINE LAYOUT: 1HP+1IP+5LP
BPR: 5.74
MASS FLOW: 3123lb/s
TO THRUST: 93,100lbt
Engine Noise Comparisons:
GE90-94B
http://noisedb.stac.aviation-civile....df.php?id=8091
Lateral Full Power - 96.5 EPNdB.
Approach - 98
Flyover - 90.7
PW 4090
http://noisedb.stac.aviation-civile....df.php?id=8110
Lateral Full Power - 96.9 EPNdB.
Approach - 99.2
Flyover - 95.2
RR T895
http://noisedb.stac.aviation-civile....df.php?id=8129
Lateral Full Power - 98.3 EPNdB.
Approach - 99.4
Flyover 93.4