What is the difference between the QXL XDDM and WDDM drivers?

Posted on October 18, 2021

If you are using SPICE to connect to a Windows VM guest, you may choose to install the QXL video driver on the guest system. The SPICE website links to a “Windows QXL-WDDM-DOD driver” and a “Windows QXL driver,” but it does not provide any information about what the difference is between the two drivers. This may lead to confusion for those unfamiliar with Windows device drivers.

The main difference is that the QXL-WDDM-DOD driver targets the Windows Display Driver Model (WDDM), while the “Windows QXL driver” targets the Windows 2000 Display Driver Model (XDDM). Windows Vista and Windows 7 support both driver models. Later versions of Windows support only the WDDM, and earlier versions (from Windows 2000) only the XDDM.