Hi Hugo,

First you need to find the boot time of your PC :

Click Windows + W to jump directly to Search, type event, and select View event logs.
In the Event Viewer, navigate to > Applications and Services Logs >Microsoft > Windows > Diagnostics Performance.
You can now view the log file that contains all events in that category. The Event ID you are looking for is 100.

As shown above, my computer had a critical boot duration of almost three minutes, due mostly to boot processes that occurred post the actual booting up.
I should note that this is not normal; I run Windows 8 on old hardware. Open the Details tab to find out what slows down the boot time of your computer.

Steps to have fast boot time in Windows 8:

Make Sure Fast Startup Is Enabled

Windows 8 comes with a built-in Fast Startup feature, which uses a hybrid shutdown to accelerate the following boot process. At shutdown, Windows partially hibernates, meaning it stores the kernel session and device drivers in the hiberfil.sys file on the system drive. On startup, the information in the file is loaded to resume the system.

To make sure Fast Startup is turned on (it should be by default), open Power Options via the Search, click Choose what the power buttons do on the left side, open Change settings that are currently unavailable on top, and then check the option Turn on fast start-up (recommended) under Shutdown settings at the bottom.
If you made any changes, click the respective button to save and restart your computer.

Disable Startup Programs

Windows 8 has a much improved Task Manager, which provides quick access to key system information, including programs loading on startup. On the Windows 8 desktop, right-click the taskbar and select Task Manager. Click More details in the bottom left and open the Start-up tab.

Disabling any processes that have a high or medium Start-up impact will improve your boot time. Select a process and click Disable in the lower right or right-click and select Disable.

Disable Startup Services

Windows automatically launches several services on startup, some of which you may not need.
Press the keyboard shortcut Windows + R to launch the Run dialog. Type msconfig and click OK.

In the System Configuration window switch to the Services tab. Here you can disable any services you don’t need. Be careful with Microsoft services and services related to your hardware; it’s better to leave them alone.
For this test, I turned off the services Computer Browser and Windows Media Player Network Sharing.


I hope this helps.

Regards,
Lokesh