For the Dreamliner, the 1B has three different model types, providing between 69,800 and 76,100 pounds of thrust. Those with a fan diameter of 111.1 inches (282 centimeters) have a baseline engine length of 184.7 inches (469 centimeters). These engines have been designed with a high-bypass function, which results in the majority of the air drawn not sucked in for combustion, but instead is ducted outside of the engine core. The GEnx has a bypass ratio of 9.1, which is one of the highest in the industry.

As a comparison, the Trent 1000, developed by Rolls-Royce, requires additional cooling as a result of lower pressure ratios. The GEnx engine, additionally, has a ten-stage high-pressure compressor, which produces a 23:1 pressure ratio. This puts it ahead of the Trent 1000 model, with an eight-stage high-pressure compressor and a 19:1 pressure ratio. While the Trent 1000 has a better bypass ratio of 10:1, the GEnx is lighter, which results in improved fuel efficiency and requires less cooling. //

The GEnx-1B is manufactured across six countries, in 12 different states at 21 manufacturing sites. According to GE Aerospace, more than 1.1 million parts make up the engine. With a high degree of popularity for the engine, it is also one of the fastest-selling high-thrust engines ever built by GE. Batesville, Mississippi, is home to a GE plant that produces the composite fan case, alongside Safran Engines in San Marcos, Texas, which lays up the third generation of the composite fan blades.