Although Windows 8 is coded to minimize reboots, Microsoft rep Steve Sinofsky confirmed that Redmond had made a “leap” in accelerating boot time due to “cooperation across the whole ecosystem.”
Indeed, according to Microsoft exec Gabe Aul, Windows 8 is is able to execute speedy startups because the kernel simply hibernates, instead of completely closing when the user session is closed.
“Compared to a full hibernate, which includes a lot of memory pages in use by apps, session 0 hibernation data is much smaller, which takes substantially less time to write to disk,” Aul explained in an official blog post.
“[Essentially], we’re saving the system state and memory contents to a file on disk (hiberfil.sys) and then reading that back in on resume and restoring contents back to memory. Using this technique with boot gives us a significant advantage for boot times, since reading the hiberfile in and reinitializing drivers is much faster on most systems (30-70% faster on most systems we’ve tested).”
Aul also noted that the new boot methodology boasts an advanced, multi-phase resume capability – which is capable of using multiple cores in parallel, effectively splitting the work of reading from the hiberfile and decompressing the contents.
“This new fast startup mode will yield benefits on almost all systems, whether they have a spinning HDD or a solid state drive (SSD), but for newer systems with fast SSDs it is downright amazing,” he said.
Of course, users who want to perform a complete shutdown due can still do so.
“We have an option in the UI to revert back to the Windows 7 shutdown/cold boot behavior, or since that’s likely a fairly infrequent thing, you can use the new /full switch on shutdown.exe.
“From a cmd prompt, run: shutdown /s /full / t 0 to invoke an immediate full shutdown. Also, choosing Restart from the UI will do a full shutdown, followed by a cold boot,” Aul added.