Apple has internally seeded a prototype next-generation iPhone to test in an iPhone 4S casing. The seed reveals that a variation of the iPad's A5X will provide 1GB of RAM to the new iPhone. An iOS 5.1 build also reveals new iPod touch information. The devices could be ready to launch simultaneously this summer.

That's according to 9to5Mac, which has examined Apple's internal new iPhone prototype seed. The report suggests that the purpose of testing the next-generation iPhone in an iPhone 4 or 4S casing is to try out a new chip without leaking any information about the new iPhone's design.

The new iPad has an A5X processor but the chip's heavy focus on graphics suggests it may not be ideal for smartphone use. 9to5Mac thinks that the iPhone prototypes Apple is testing have a variation of the A5X's S5L8945X architecture, aiming to give the next iPhone the 1GB of RAM that the new iPad boasts.

9to5Mac claim to have also investigated a file inside of an internal iOS 5.1 build, which has revealed what's expected to be a new iPod touch, internally labelled iPod 5,1.

The current iPod touch label is 4,1, so 9to5Mac predicts that the fifth-generation iPod touch could have major internal changes. This could include an A5 or A5X-like chip similar to the one being tested for the new iPhone.

9to5Mac estimates that the fifth-generation iPod touch could launch alongside the new iPhone this summer.