It's increasingly difficult to do power saving in modern laptops with highly integrated SoC - a single component can prevent the entire system from entering a deeper power saving state. In the old days, CPU and graphics were basically everything, but there can be an endless number of traps today, a SATA driver, an audio driver, or a PCI bridge in this case, not to mention that many subsystems are poorly documented. And even if the potential of power saving in a device driver is identified, it's often plagued with mysterious bugs (the Window driver may include nonstandard workarounds).<p>Only Intel knows everything, I guess even Microsoft doesn't (try running Windows without all the Intel chipset drivers installed...). If you take a modern laptop and put Linux on it, it's possible that you'll only able to get 50% of the battery life. And there's nothing you can do about it.