Qualcomm: Win32 apps have same impact on battery life on ARM laptops as x86

Win32 programs do not have a major impact on the battery life of laptops with Snapdragon socs. That’s what chip designer Qualcomm claims. The programs run via emulation x86 software and often emulation is accompanied by loss in performance and battery life.

The difference in battery life between the regular version of Windows 10 and Windows 10 S, the version without Win32 programs, should be comparable to that of laptops with Intel processors, Qualcomm claims. It is unknown how that is possible, as Windows runs on ARM with x86 emulation.

Microsoft uses the same Windows-on-Windows layer for emulation as it does for x86 software emulation on 64-bit systems. Because the emulation of x86 on ARM processors cannot be done in hardware, as with x64 processors, Microsoft uses something it calls Compiled Hybrid Portable Executables. Those are dlls containing ARM code. That code stores the system in memory for quick use. In addition, there is a software emulator in the system. The x86 emulation is only needed for Win32 programs. Software made for the Store, so-called UWP apps, are not programmed for a specific processor architecture.

Qualcomm’s claim cannot yet be tested, because none of the manufacturers that make a laptop with Windows and ARM processor has sent out review copies. The manufacturers claim a battery life of twenty hours or longer for announced models. Those laptops run on a Qualcomm Snapdragon 835, the same soc as many recent high-end smartphones.