Side By Side Comparison of Panasonic GD21 and Panasonic GD31. Compare Processor, display, RAM, Storage and other features here. You can quickly compare Panasonic GD21 and Panasonic GD31 smartphones just by looking at their ratings and results showing "winner" and "runner up." There is also a short analysis comparing different features of Panasonic GD21 and . You can also look at each hardware feature individually to perform your analysis while comparing mobile phones.