In a statement this morning, Apple claims that it's sold more than 4 million iPhone 4S units in the three days since its launch on Friday. This represents more than double the sales of its predecessor the iPhone 4.

1 million of these 4S units were sold within the first 24 hours of the phone being available to preorder -- an increase of around 66% over the previous year. By comparison, the iPhone 4 peaked at 600,000 preorders in a single day.

The iPhone 4S, while looking superficially identical to the iPhone 4, is a complete overhaul, featuring a new dual-core processor, a vastly improved camera that shoots video in 1080p, improved graphics processing and the voice-activated personal assistant Siri. While it's not the iPhone 5 many were hoping for, it is a significant improvement over past revisions.

The new model iPhone is seeing many developers upping their efforts when it comes to gaming. Firemint's Real Racing 2 offers considerably enhanced graphics and wireless 720p video output when played on a 4S. Rockstar's upcoming Grand Theft Auto III port will only work on a 4S (or iPad 2). And a number of other 3D-heavy games are offering graphical improvements such as fancy specular lighting effects when played on the 4S.

This article originally appeared on as iPhone 4S Sales Top 4 Million in First Weekend