In addition to the alleged ?iPhone 6s? case, the 9to5Mac he also put his hands on what would be his logic board. It is not easy to analyze the news just by looking at these small pieces, but one that can be immediately identified has to do with the speed of 3G / 4G / LTE navigation.
As we can see, this logic board has Qualcomm's MDM9635M chip (also known as 9X35 Gobi modem platform), which has twice the performance (download via cellular network) than the 9X25, present on iPhones 6/6 Plus.
In theory, instead of the 150Mbps of the current iPhones, in the next one we will have a download rate over the operators' networks of up to 300Mbps. The upload would remain the same, 50Mbps. Needless to say, we will hardly be able to test this capacity of the MDM9635M here in Brazil, right?
But the news doesn't stop there: this chip is also more energy efficient. In parallel, the logical card of the ?iPhone 6s? would be slightly smaller than that of the iPhones 6/6 Plus (this chip from Qualcomm, for example, manufactured using a 20 nanometer process versus 28 nanometers from its predecessor), opening up more space for the battery. Putting it all together with the optimizations that Apple is making on iOS 9 (the new operating system promises to improve the battery life on iPhones by up to 1 hour), we will most likely have real / significant battery gains in the future generation of the phone.
It was also said that the new iPhone's motherboard is slightly narrower and more compact than that of the iPhones 6/6 Plus, which could mean extra space for a modestly larger battery.
As expected, the ?iPhone 6s? has everything to be better than the current iPhones in all aspects, although the differences are not glaring. This is how Apple works: refining, improving what is already good. Comparing one generation to the previous, the differences may seem small; but when you compare a device with 2-3 generations past, you realize how well everything has evolved.