Current commercial high-end machine

Current commercial high-end machines can support gigabytes of physical memory (e.g., SPARCCenter 2000, SGI Challenger), and newer machines are expected to reach terabytes 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?