The new version is PowerPC native, finally abandoning the Motorola 68k processor. Since there is no more 68000-based Amiga hardware being produced, AmigaOS 4.0 will run on some PowerPC hardware, which currently only includes A1200, A3000 and A4000 with PowerPC accelerator boards and AmigaOne motherboards. Amiga, Inc.'s distribution policies for AmigaOS 4.0 and any later versions require that for third-party hardware the OS must be bundled with it, with the sole exception of Amigas with Phase 5 PowerPC accelerator boards, for which the OS will be sold separately.
AmigaOS 4.0 Final introduced a new memory system based on the slab allocator that supports "on the fly" defragmentation of the memory space, memory allocation on mass storage devices (paging memory, implemented since AmigaOS 4.1) and Symmetric multiprocessing (not implemented yet).
Features, among others:
Fully skinnable GUI
Integrated viewer for PDF and other document formats
Support for PowerPC (native) and 68k (emulated JIT) applications
Support for modern hardware devices
Faster memory allocation system, similar to what's used on Solaris
2 GB file size limit removed
Integrated Picasso 96 2D Graphics API
Integrated Warp3D 3D Graphics API