There is a benchmark proving that. With cache enabled, it's actually going way beyond that.
https://github.com/fuse-box/angular2-example
Try using webpack on this project. And compare to fuse-box. You will get a convincing result.
1) Fusebox is not just a bundler it's a loader with a pretty comprehensive API, which WebPack does not offer.
2) FuseBox supports typescript out of the box. It compiles and bundles it in a matter of milliseconds
3) Unlike WebPack, FuseBox does not modify and regenerate the source code. That's a performance boost.
There is so much more,