9to5Mac reports on details for the next-generation iPhone from a source with access to a prototype of the device and access to a beta of iOS 6 targeting that device. Among other things, the details reveal the application processor, the graphics processor.
The next generation iPhone will run an application processor identified as S5L8950X. According to the report, the processor will carry the A5 branding, rather than being called the A6. As MacRumors points out, that processor first showed up in iOS 5.1 betas alongside the S5L8945X processor that arrived as the A5X in the current iPad.
As far as graphics go, Imagination Technologies is said to be supplying the chip again. At the moment, it is being referred to as SGX543RC*. That name however seems to be a codename and does not correlate with any official versions of the SGX543 platform.
Finally, the iOS 6 build is said to be running on a Darwin kernel version of 13.0.0. This is above the 11.x.x used in iOS 5 and OS X Lion, and even above the 12.0.0 that is used in OS X Mountain Lion.