Lumia is a 4 inch device with 512mb rab and 8gb internal memory which expandle to 64gb. It got 1.0 snapdragon krait processor and 5mp megapixel auto focus without flash but it perfom very well. Thought it got only 512mb ram but you will find no lag in window phone.
Front camera is not available. With adreno Gpu 305 gaming experience is good. Also 4 inch phone can be used within one hand easily. Due to window 8.1 update one can install whole in memory card also.