The amount of power consumed by Angry Birds was comparable to that of a web browser. However, the study suggests its power consumption would be drastically reduced without ads. ((Lucas Jackson/Reuters))

Popular smartphone games Angry Birds and Free Chess consume up to three-quarters of their energy delivering advertising to Android devices, a new study has found.

"Free apps like fchess and angrybirds spend under 25 to 35 per cent of their energy on game play, but over 65 per cent to 75 per cent on user tracking, uploading user information and downloading ads," reported the study by researchers Abhinav Path and Y. Charlie Hu at Purdue University in West Lafayette, Indiana and Ming Zhang at Microsoft Research.

That suggests the same apps would consume drastically less power without ads. However, ads provide revenue for the developers, allowing them to make games available to download for free.

The study, already published online, will be presented at EuroSys 2012, a conference focused on IT systems software research and development that will take place in Bern, Switzerland from April 10 to 13.

Abhinav and his colleagues developed a tool called "eprof," which profiles energy use in smartphone apps.

They used the tool to profile popular Android apps while they were running on 3G wireless networks.

All five apps consumed 0.35 to 0.75 per cent of a smartphone's full battery in about 30 seconds — "a rate that could discharge the entire battery in a couple of hours," the study said.

However, the amount of power consumed by the free games was comparable to that used by the web browser, a New York Times app, and Mapquest, which all had user tracking functions.

The researchers used their tool to successfully find energy-sucking bugs in some apps. They also used their findings to show how energy consumption by some apps could be reduced by 20 to 65 per cent.