The standard NT 4.0 kernel (NTOSKRNL.EXE) relied on "terminal services support" being off. TSE turned it on. This required a complete reworking of the Graphics Device Interface (GDI). In a standard NT environment, drawing a window happens locally on the video card. In TSE, the server maintained a "virtual display" for every single connected user.
: Windows NT 4.0 TSE was designed to be compatible with a wide range of software applications and hardware. It also integrated well with other Microsoft products and technologies of the time, such as Microsoft Office and SQL Server. windows nt 4.0 terminal server edition