The PA-8900 is a slightly tweaked PA-8800 featuring a doubled L2 cache and a higher clock frequency. It is probably the last processor of the PA-RISC family, no more new PA-8x00s will be released. Future systems will be based around Itanium-family chips, although since HP dropped its line of Itanium-based workstations it seems the PA-8900-powered C8000 workstation will be one of the last HP-UX workstations (together with the similar Itanium-based zx2000).
Information on the PA-8900 is generally scarce, it seems there was not much interest releasing many details on the inner workings and architecture, no whitepapers or more detailed articles could be found.
PA-8900 was used in rp3410, rp3440, rp4410, rp4440, C8000, L1500-9X (rp5430), L2000-9X (rp5450) (probably), N4000-9X (rp7405, rp7410) (probably) and Superdome.
- PA-RISC version 2.0 64-bit
- Twenty functional units: four integer ALUs, four shift/merge units, four complete load/store pipelines, four Floating Point multiply/accumulate units, four Floating Point divide/square root units
- Two address adders
- 240-entry fully-associative dual-ported TLB per core
- 32-entry BTAC (Branch Target Address Cache) per core
- 2048-entry BHT (Branch History Table) per core
- Dynamic and static branch prediction modes
- 4-way superscalar
- 0.75MB I and 0.75MB D on-chip L1 caches per core