- Physical address sizes increase by 2 bits every 3 years, tracking DRAM density growth, and need to cover a 4:1 to 16:1 range to accommodate future memory sizes.
- Virtual memory pressure often exceeds physical memory by at least 4x, driven by memory-mapped files and large file systems with holes, accelerating address space demands.
- Extrapolating from current trends, a transition from 64-bit to 128-bit addressing would occur around 2043 for physical memory, or earlier (circa 2020) if virtual memory pressure increases.
- Practical concerns like die space, wire delays, and the complexity of wide datapaths (e.g., 1024-bit) make such architectures unlikely without strong justification, with 128-bit being the more realistic near-term goal.