iPhone 6S is coming up with system in package accompanied with printed circuit board. Basically SiP makes circuit board of iPhone much more compact and ensures that the phone will take very less time to build. iPhone 6S will have much smaller A9 chip than its regular A8 which presently seen in phones.
Moreover, according to the rumors 32 GB will be the base storage for next iPhones .As know the iPhone 6s will be coming up in different variants of 16GB, 64GB and 128GB.
Apple is trying to work on making its hardware much smaller this only means iPhone will be making place for new features to be in. Apple claimed that many new features will b part of Apple iPhone 6S. Wait is still till September 9.