With the same CPU, GPU (at least integrated), system bus, RAM, etc. how did Apple achieve then an extra hour of battery life on the mid-2015 model? Is it because of the "time saved" doing anything disk intensive due to the faster PCIe drive?
It's the SM951, but without NVMe.The new SSD is probably where it's coming from. I think Apple is using the Samsung XP951 in the new MBP (I'm not 100% certain though) and I know they have a drastically reduced idle power consumption over the XP941 in the 2014 MBP (2mW vs 50mW). I'm not sure what the difference is in load power consumption though.
Aside from the SSD, there might be a bit of marketing involved (e.g. I can get 10+ hours out of my 2014 MBP if I turn the display brightness down, turn off Bluetooth and don't do anything strenuous). Point being, they probably could have marketed the 2014 MBP as 9 hours and gotten away with it as well.
yeah its probably a sum of things.
CPU that can do more things in less time leading to less power usage.
GPU that can do more things in less time leading to less power usage.
Slight battery bump
More efficient software/drivers drivers then when the original rating was done.
faster RAM that can do more things in less time leading to less power usage.