As you know, APU Trinity has an integrated memory controller shared by both CPU and GPU. According to the source, Kaveri will be the next step - the GPU and CPU will be a single memory address space. This allows, in principle, eliminate the losses associated with copying data, and will further integrate the GPU and the CPU, increasing productivity.
Configuration of Kaveri includes GPU architecture based on GCN, used in the discrete GPU generation Southern Islands (Radeon HD 7000) with no rudiments of architecture VLIW-4, used in the GPU of the Radeon HD 6000.
As for the CPU, this part will be built on the Steamroller architecture - further development of Piledriver. However there is no information on DDR4 Support.
APU Kaveri will come out roughly the same time with processors Intel Haswell, which will not have a single address space for x86-compatible cores and integrated graphics.