Windows Enterprise Client Boot and Logon Optimization – Part 10, Boot Phase – POST

This post continues the series that started here.

My last five posts have been setting you up for the analysis of individual boot phases. This post and the next five will discuss each phase.

For each phase, I’ll discuss phase activities, measurement of phase duration, issues that commonly occur and investigation of those issues.

Today I’ll start with a simple phase – POST.


As seen in the diagram, POST is too early to be traced using Windows Performance Recorder (WPRUI).

Boot Phase POST – Phase Activity

POST is the first stage of system start-up –

  • Hardware is powered on and initialized
  • Firmware performs a Power-on-self-test (POST)
  • MBR is read (BIOS only)
  • Boot manager is launched (bootmgr.exe / bootmgfw.efi)
  • Winload.exe / Winload.efi is started and boots Windows

Boot Phase POST – Measurement

As I’ve already mentioned, POST occurs too early to be recorded using an analysis trace. Systems prior to Windows 8 have no reliable way of measuring POST.

Beginning with Windows 8, ACPI 5.0 systems record POST duration (ms) in –

HKLM\System\CurrentControlSet\Control\Session Manager\Power\FwPOSTTime

Boot Phase POST – Potential Issues

BIOS/Firmware configuration may introduce a delay -

  • PXE boot enabled?
  • Device boot order may delay start-up

A Dual/Multi-boot configuration introduces a delay as long as the menu timeout.

Boot Phase POST – Remediation

Update BIOS/UEFI firmware and optimize configuration.


Issues that may occur during POST are limited but misconfiguration could introduce significant delays. Ensuring system BIOS/UEFI firmware is updated and properly configured is essential in optimizing the user experience.

Next Up

Boot Phase – OS Loader and Kernel Initialization

Comments (2)
  1. anonymouscommenter says:

    My peer Mark Renoden, Roger Southgate and Scott Duffey, whom I had the pleasure of meeting in Sydney

Comments are closed.

Skip to main content