Kernel-mode driver architecture: New in the WDK for Windows 8.1
Windows 8.1 includes a new set of timer routines. Kernel-mode drivers can use the ExXxxTimer routines to manage high-resolution timers and no-wake timers.
The accuracy of a high-resolution timer is limited only by the maximum supported resolution of the system clock. For more information, see High-Resolution Timers.
To reduce power consumption, a no-wake timer avoids unnecessarily waking a processor from a low-power state. For more information, see No-Wake Timers.