To estimate the CPU power required, use the number of active users. It is very important to understand the person's definition of active user and the frequency of the demand upon the server. With a long think time between requests, it is possible to support more active users on the high-performance RISC servers. Certain applications such as CAD may require more memory. Local Clients run in the X Terminal and use its memory.
Examples are terminal emulators and window managers.
It is very common for users to overconfigure the X Terminal memory. Putting memory into the X Terminal does not gain you any application performance unless you are using the backing store feature, which allows the fast repainting of hidden windows. Without this feature activated, large drawings must be redrawn from the host, which is slow and aggravating for the user. The caution is that this feature requires a significant amount of memory in the X Terminal, e.g., an extra 2 to 4 MB of memory if the hidden portion of the window is large and has complex graphics. This would typically be used in CAD type applications or graphics applications that have overlapping windows.