A HP fornece um guia como ativar a GPU:
Install the HP Software Framework as found here.
Next, uninstall all ATI/AMD software through Programs and Features.
Go to www.hp.com and select Support and Drivers at the top.
Select Software and Driver downloads and enter your product model or product number.
Select the most recent operating system matching your installation of Windows 8's bit architecture. For example, Windows 7 64bit for Windows 8 64bit.
Download the ATI graphics card driver.
Run the file once it is finished downloading.
Let the extraction process finish, but cancel the installation when prompted to continue it after the extraction. Take note of where this is extracted to. By default, this should be c:\swsetup\.
Here, there should be a setup.exe for installing the ATI driver. Right-click this and select troubleshoot compatibility.
Follow the compatibility troulbeshooter and select the suggested fixes. On one screen, there will be a test program button. Click this to begin the installation.
Follow the installation and it should finish successfully.
Once finished, right-click the desktop to verify the configure switchable graphics option is listed.
Experimente, talvez funcione para você também.