/sys$common/syshlp/helplib.hlb Sys Parameters, MPW_LOWAITLIMIT  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    MPW_LOWAITLIMIT specifies the threshold at which processes in
    the miscellaneous wait state MPWBUSY are allowed to resume.
    MPW_LOWAITLIMIT increases system performance for fast processors
    with large memories by reducing the amount of time processes
    spend in the MPWBUSY wait state.

    MPW_LOWAITLIMIT has the AUTOGEN and DYNAMIC attributes.