Whenever possible, display drivers should use the features of the CPU to optimize performance. This is particularly important for drivers used in multimedia versions of Windows.
A display driver can determine what CPU is present and in what mode Windows is operating by examining the __WinFlags variable or by calling the GetWinFlags function. If the CPU is a 386 or 486, the display driver should take advantage of the CPU's 32-bit registers to manipulate data and to index huge arrays.