Amazon’s mobile site produced the fastest iPhone access time across three major service providers in April, says Compuware Gomez. Last month, Amazon.com produced an average iPhone mobile response time of 3.05 seconds.

M.Sears.com came in second in iPhone testing among large web retailers an average response time of 3.63 seconds, followed by OfficeDepot.com (3.69 seconds), LLBean.com (4.63) and HSN.com (5.26).

Gomez measures the average iPhone response time for the three major service carriers: AT&T, Sprint and Verizon. Testing for all 20 retailers took place once per hour per carrier from two U.S. locations (Virginia and California).

Gomez measures response time as the end-to-end time elapsed while downloading each mobile site.

Click here to see the full test results.