Indirect rendering can be shown to perform well if the network is sufficiently fast (Gigabit Ethernet, for instance), if the application does not dynamically modify the geometry of the object being rendered, if the application uses display lists, and if the application does not use a great deal of texture mapping. Many OpenGL applications, however, do not meet these criteria. To further complicate matters, some OpenGL extensions do not work in an indirect rendering environment. Some of these extensions require the ability to directly access the 3D graphics hardware and thus can never be made to work indirectly. In other cases, the user's X display may not provide explicit support for a needed OpenGL extension, or the extension may rely on a specific hardware configuration that is not present on the user's desktop machine.