which is the better way to test my ios app in iPod or in iPhone?

As we all know that iPod touch is having less memory than iPhone, but still i have a confusion in my mind that which is the bett开发者_高级运维er way to test my application because i am developing an iPhone app which is for both ios3 and 4 when i test my app in iPhone4 there is no memory warnings and crash but if i test the same app in my iPod touch with 3.1 ios at some time crashing will happen with level2 memory warning,"Failed to launch simulated application: SpringBoard failed to launch application with error: 7" and etc. I don't know what is the problem, is this my code problem or this is due to lower memory device problem?

Any help is appreciated in advance, thanks.

Yes this is a memory issue. Different generations of iPod touches have different amount of memory, just as different generations of iPhones have different amount of memory.

It is always a good idea to test your app on the oldest device that supports the oldest version of iOS you intend to support.

Wikipedia has an extensive list of the OS versions including the oldest supported devices: http://en.wikipedia.org/wiki/IOS_version_history

Most studies made suggest that at least 90 to 95% of all users have iOS 4 or later installed. So you should also ask yourself if supporting anything older than that is worth your extra time, how likely is a user that can not be bothered with a free OS upgrade to purchase your app? http://www.cocoanetics.com/2011/08/ios-versions-in-the-wild/