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

    SYSPFC sets the number of pages to be read from disk on each
    system paging operation.

    This special parameter is used by Compaq and is subject to
    change. Do not change this parameter unless Compaq recommends
    that you do so.