This old processor is what is used in the iPhone 5C. The iPhone 5S processor is called the Apple A7 chip, the iPhone 5C's the A6 processor. There's not a great difference in terms of the number and speed of the cores it uses, but theoretical performance is much better in the iPhone 5S.
Just so, do the iPhone 5s cases fit the 5c?
An iPhone 5s and an iPhone 5c have slightly different dimensions and so a case designed for iPhone 5s is probably not going to fit an iPhone 5c - however, if the case is slightly elastic or just imperfectly fitting, it might still work.
Are iPhone 5 and 5c the same size screen?
The iPhone 5 and 5c are NOT exactly the same. They may operate and run the same but apple changed the internals so that most of the parts are NOT compatible between the two models, screen included. You will not be able to use a iPhone 5 screen on a iPhone 5C then have a different digitizer connectors.
Which is bigger iPhone 5s or 5c?
Processor Speed: The 5S is Faster. The iPhone 5S has a faster processor than the 5C. The 5S sports an Apple A7 processor, while the heart of the 5C is an A6. The A7 is newer and more powerful than the A6, particularly because it's a 64-bit chip (the first in a smartphone).