VMS Help Sys Parameters, SYSMWCNT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    SYSMWCNT sets the quota for the size of the system working set,
    which contains the pageable portions of the system, the paged
    dynamic pool, RMS, and the resident portion of the system message
    file.

    While a high value takes space away from user working sets, a low
    value can seriously impair system performance. Appropriate values
    vary, depending on the level of system use. When the system is
    running at full load, check the rate of system faults with the
    MONITOR PAGE command of the Monitor utility. An average system
    page fault rate of between 0 and 3 page faults per second is
    desirable. If the system page fault rate is high, and especially
    if the system seems to be slow, you should increase the value of
    SYSMWCNT. However, do not set this parameter so high that system
    page faulting never occurs.

    SYSMWCNT has the AUTOGEN, GEN, and MAJOR attributes.