Basemark OS II Free is a benchmarking app for Windows Phone that allows you to measure the performance of your device.
Basemark OS II Free performs a range of performance checks, including system, memory, graphics, web browsing and camera. Once the tests have been run you'll be given an overall score, plus a breakdown of each attribute. You can then compare these results against other devices.
If you want to learn more about how your hardware matches up, Basemark OS II Free is a handy tool.