However, according to this article, VT-d is important even for games.
PC enthusiast customers and companies running corporate datacentres looking to buy into the new Sandy Bridge-E platform may want to wait a little while before handing over their hard-earned money to Intel. The initial batch of C1 revision Sandy Bridge-E processors have a bug – “errata” in Intel terminology – in them with VT-d, which means that hardware accelerated virtualization doesn’t work properly with them (software only mode is unaffected). The feature when working properly, allows all hardware acceleration to work on the hosted operating system (virtual machine). This would allow things such as hard drive controllers to work, plus applications such as high-powered 3D games, typically First Person Shooters, to run at nearly full speed and the full Windows Aero desktop to be displayed on the hosted OS, as the hardware features of the graphics card can be used. Therefore, working VT-d is a critical feature for these kinds of applications.
If it is
important for games, I don't know what to do. I was planning on buying a 3930K in a few days.