Current commercial high-end machine

Current commercial high-end machines can support giga-bytes of physical memory (e.g., SPARCCenter 2000, SGI Challenger), and newer machines are expected to reach tera-bytes of physical memory. Current workstations support up to 0.5 giga-bytes of memory or more (e.g., SPARCStation-10). The question is how will large amounts of physical memory, especially when coupled with support for multiple pages sizes, affect page replacement?