IPhone 4S users transfer on average three times more data than users of the older iPhone 3G model which was used as the benchmark in a study by telecom network technology firm Arieso.
Data usage of the previous model, the iPhone 4, was only 1.6 times higher than the iPhone 3G, while iPad2 tablets consumed 2.5 times more data than the iPhone 3G, the study showed.
The spike in data usage for iPhone 4S users is likely not fully explained by the debut of Siri on the device, as a study by Ars Technica conducted soon after the device's launch revealed an average of 63 KB of data used per query. With even high-use users reporting making an average of fifteen queries per day, that would equate to approximately 30 MB of usage per month if all queries were performed over cellular networks.
As noted by ZDNet, other factors such as iTunes Match, iCloud, device speeds, larger photos, and "new toy syndrome" are also all likely contributing to the increased data usage.
Data usage has become a major area of concern for carriers as they seek to deal with the surging demand from smartphone users that are growing rapidly in number and in their demands for content. While a number of carriers such as AT&T and Verizon launched the iPhone with "unlimited" data plans, most carriers have now switched to tiered data plans for new customers as they seek to encourage more modest data consumption and extract additional revenue from the heaviest data users.
Consequently, customers have had to become more aware of their data usage needs as they determine which data plan to sign up for in order to avoid what can be significant overage charges.