A lot of people have been telling me things like, “Of course Windows 7 Beta 1 doesn’t work with XP drivers.” As if there’s no shot that it’s even supposed to work. Well, it works in Vista and it’s a key feature. Microsoft rearchitected the graphics architecture in Windows Vista from the XP Display Driver Model (XDDM) to the Windows Display Driver Model (WDDM). In this new display driver model, Microsoft introduced new requirements for video hardware and forced all graphics driver vendors to write new drivers for their devices. This obviously meant that there was graphics hardware out that didn’t meet the new requirements. More specifically, a lot of extremely common graphics cards from Intel did not support WDDM. Fortunately, there is a compatibility layer in Windows to allow XDDM drivers to still work. When using XDDM drivers, some advanced graphic features that rely on the new WDDM model are disabled, notably the Windows Aero theme. Although the Windows Aero theme is visually pleasing, it is not the only highlight in Windows Vista or Windows 7.
Most people will buy Windows 7 on a new PC, but I believe Windows 7 will sell better in retail then any other Windows OS before. With the performance and usability gains, Windows 7 is very exciting to computer users worldwide, and I do not doubt that many will decide to take the plunge and upgrade their computer. Computers running XP today will have the chance to run Windows 7, the OS of tomorrow. Some of these computers might have graphics cards that are DX9 compatible, but do not support WDDM. Take for example a thin, light and tiny 12” laptop with a 1.8ghz Pentium M processor, 1gb of RAM and a 4 hour battery life. Sounds like an awesome netbook to me, but instead it’s a 4 year old Dell Inspiron 710m. It came with Windows XP, and Windows Vista runs very slow on it. The only chance for this machine to run a newer operating system is Windows 7. There are a lot of older machines from 4+ years ago that should work just great under Windows 7, as they still have better specs then present day netbooks.
The incredible performance exhibited from Windows 7 has opened up the scenario of people upgrading their older machines to the new version of Windows. People will be expecting their hardware to be working out of the box with Windows 7, including video cards that do not have WDDM drivers. It’s extremely unfortunate that XDDM drivers do not function properly on Beta 1, as it’s a key scenario that needs to be tested. Not to mention, a whole class of machines with XDDM only graphics cards will undergo much less testing. Let’s hope XDDM is fixed in the next release of Windows 7 from Microsoft!
Jan 13 2009, 06:21 AM