Windows 8.1 on Sony Vaio VGN-Z650N/B Hybrid Graphic

I bought my Vaio VGN-Z650 notebook on April 2009. It's a Core2Duo@2.53Ghz Notebook with an Hybrid graphic (intel integrated + nVidia 9300M discrete)
Unfortunately this notebook came with Windows Vista Professional preinstalled and when Windows 8 came out I choose to update the OS to get rid of it.
Sony made the drivers for Windows 7 (32/64 bit) and most of them work fine except the video card one.
You can always leave the nVidia card unrecognized and default to the Intel integrated drivers pre installed by Windows but this Notebook is a bit outdated and maybe you want to use it at "full power" to keep it a bit longer.

In this short post I'll show how to set up only the graphic card both on Windows 8 and 8.1 to help you be up and running without wasting time.

For further details and to find the drivers please refer to this thread which solved all my problems.

The Drivers
Please be sure to download the right driver for the system: for the VGN-Z with 9300M card are the one made by Andrew08 (to which we are all grateful) named "26308 2020 101112".
before starting the "Stamina - Speed" switch should be set on Speed.

Installation
In order to use this driver you have to disable the unsigned driver enforcement which is by default active in windows 8 and then install the driver:

1. Press + R to open a Run Window
   
2. Enter shutdown.exe /r /o /f /t 00
3. Click the "OK" button
4. System will restart to a "Choose an option" screen
5. Select "Troubleshoot" from "Choose an option" screen
6. Select "Advanced options" from "Troubleshoot" screen
7. Select "Windows Startup Settings" from "Advanced options" screen
8. Click "Restart" button
9. System will restart to "Advanced Boot Options" screen
10. Select "Disable Driver Signature Enforcement" (option number 7)
11. Once the system starts, install the drivers (it may take some time)
12. Open a Command Prompt as Administrator
13. In the Command Window type:

bcdedit -set loadoptions DISABLE_INTEGRITY_CHECKS

bcdedit -set testsigning ON

1. Reboot
2. If all is ok this time when you log in Windows the Speed light near the switch should be on

While working you should note some annoying flashing of the display, to solve this problem:

1. Open the Nvidia Control Panel Client
   "C:\Program Files\NVIDIA Corporation\Control Panel Client\nvcplui.exe"
2. Click Customize
3. Click Create Custom Resolution...
4. Open Timing
5. Select CVT
   
   

1. Click Test
2. Save this configuration, exit the Control Panel Client and reboot
3. The flickering should be gone