Alpha 21264 Technical Reference

Architecture-level detail for the Alpha 21264, the processor at the heart of the UP1000 and UP2000 motherboards. For the marketing overview see the Alpha 21264 product page (or 21264A for the higher-clocked revision).

Core architecture

• Third-generation 64-bit Alpha microprocessor, four-way superscalar, out-of-order execution
• Speeds from 500MHz up to 750MHz depending on board and revision
• Alpha Motion-Video Instructions (MVI) for real-time video/3D and DVD authoring (MPEG-2, AC-3)

Cache & bandwidth

• On-chip split L1 cache: 64KB instruction + 64KB data
• Flexible off-chip L2 cache, 2–8MB depending on board configuration
• Over 3.2GB/s L2 cache bandwidth, over 2.6GB/s memory bandwidth (board-dependent)

Benchmarks

Alpha 21264-based systems have historically scored over 30 SPECint95 and 50 SPECfp95 — performance aimed at workstation-to-enterprise-server workloads: commercial servers, web servers, and real-time visual computing.