Owners of iPhone, Android or Windows Phone smartphone devices have consumed 35 times more mobile data than a typical cellphone user, an annual report by Deloitte said.
The growing rate of data consumption could see a 50-fold growth in wireless traffic by 2016, it said.
The likely outcome will be a slowdown in data speeds and connection problems, mostly felt in cities, on networks with the most subscribers and in peak wireless hours, Deloitte said.
Users could see two to three times as many failed attempts to connect, three to four times as many dropped calls or frozen web browsing, and both 3G and 4G speeds 50-90 percent lower than expected, the company said.
"In the worst situations, download speeds may be under 1Mbps for lengthy periods of time, making video streaming impossible and even web browsing difficult."
Wireless traffic has more than doubled each year since 2009 and the increasing numbers of smartphones and tablets in use will only make the problems worse, Deloitte said.
Attempts to free up additional bandwidth are lagging behind traffic growth, the report said.
"Demand for wireless bandwidth will likely attempt to outstrip these improvements in supply for at least several years. Major metropolitan areas in some geographies should expect to see continued deterioration in end-user experience," the Deloitte report concluded.