I recently bought Sony Xperia M which came with 4 gb internal memory, out of which 2 gb were free for the user to use.I wish to buy an SD card, class 10, so that I can download and play games of large file sizes on my phone. My concern is to know how to do this? Is it a good idea? And has anyone else tried it ? I don't wish to root my phone as it might void the warranty. Thank you in advance!