The best way to know is to open the laptop's back panel and check what type of RAM is already installed. In this example, the RAM module above uses DDR3 as labeled on the sticker. Now that you ...

Rate Acer Aspire 5742G Ci3/320GB/1G Graphics Core i3 - (3 GB DDR3/320 GB HDD/Windows 7 Home Basic/1 GB Graphics) Notebook ...