When you attempt to update the AMD processor driver on your x64 version of Windows Server 2003, or Windows XP, the original Microsoft in-box driver is installed, causing you to loose features on your multiprocessor computer.
This behavior will occur if a newer AMD processor driver was previously installed, because the driver ranking process assigns the in-box processor a higher rank that the newer AMD driver. The in-box .inf file has a hardware ID that is more accurate than the AMD .inf file.
To workaround this issue:
1. Right-click My Computer and press Manage.
2. Select Device Manager and expand Computer in the right-hand pane.
3. Right-click the processor you want to update, and press Properties.
4. Select the Driver tab.
5. Press Roll Back Driver.