Does the X Server use too much RAM, and should that RAM usage dramatically increase during an X session?
The short answer is “no”, but the real situation is much more complex. The important thing to understand is the difference between physical and virtual RAM. Your PC can address much more RAM than is physically present on your computer. The total address space which your computer can use is called its “virtual memory map.” Applications can ask for huge chunks of RAM from the memory manager, and they will be assigned however much of the virtual memory space they require. They can be assigned much more virtual RAM than even exists in physical RAM on your computer! The Linux Kernel manages what portion of the virtual memory map is actually stored in physical RAM at any point in time. The basic algorithm is “use it or lose it.” If an Application’s RAM is unused for some period of time, the Kernel will write that physical RAM to disk, and free up the block of physical RAM for other uses. The virtual allocation remains unchanged. Our X Server uses about 2 MB of virtual RAM and that stays cons
