Here is a recently published list of the 10 fastest smartphones in the world, ranked by both download and upload speeds.
Researchers at Aalto University in Finland have tested real-world download and upload speeds for more than 4,500 smartphones on networks around the world. Interestingly, on the download side, the fastest phone in the world is more than a year old.
The fastest downloading smartphone is not an iPhone but clock-speed is not the whole story. Software is a huge piece of the puzzle, as is display resolution and UI. The speeds at which a smartphones can send and receive data also plays a huge role in ensuring a smooth user experience.