I strongly trust notebookcheck reviews however this review of the XPS 15 9570 FHD with i5 seems a little too good to be true when concerned with its battery life.
Quote: "The runtime on battery is one of the best that an XPS 15 has ever offered in our tests: The lights only go out after 15:42 hours in our Wi-Fi test at 150 cd/m² (dimmed by 6 levels, Dell energy profile set to "quiet"). We ran the test a second time, which confirmed this result."
Almost 16 hours of light Wi-Fi usage battery life on the FHD i5 model seems incredible to me, however what specifically has changed from the 9560 that made the 9570 so much more frugal? The exact FHD panel (Sharp SHP1453 LQ156M1, as notebookcheck said was in their reviewed model) has been in use in the 9550 and 9560 FHD models already, so this isn't some new more power efficient display. Then the next part, the CPU, should by all means be on par with, if not consume slightly more power on average than the i7 7th gen CPUs, as the 8th gen CPUs have 2 extra cores, and this has been proven with other 7th gen laptops that have been refreshed with 8th gen parts - they all show similarly slightly increased power consumption on average.
Additionally, I haven't yet found another source to backup notebookcheck's 15 hour (Wi-Fi browsing) light usage battery life, with all other reviews showing battery life of the FHD i5 9570 as being in the same ballpark as last year's FHD i5 9560.
So yet again, this comes back to my main question - is the 9570 actually more frugal, and if so, how and what exactly has caused this significant improvement in battery life? Or otherwise, is this a mess up on notebookcheck's end?
Thanks