The AlphaServer 8200 and 8400 are the largest Alpha systems Digital built around the 21164, and they use the same system bus, processor modules, memory modules, and I/O port modules. ¹⁾ The 8200 is a 19-inch rackmount cabinet with single-phase power for office and laboratory use, while the 8400 uses the DEC 7000 cabinet with three-phase power for computer rooms. ²⁾ The EV6 AlphaServer GS60 and GS140 are the same machines with 21264 CPUs.

Except where noted, the following comes from the technical summary. ³⁾

• TLSB system bus with a 40-bit command and address path and a separate 256-bit data path with 32 ECC bits, run synchronously at a submultiple of the CPU clock: 75 MHz with 300 MHz CPUs for 1.6 GB/s, and 87.4 MHz with 350 and 440 MHz CPUs for 1.87 GB/s
• AlphaServer 8400: nine bus slots, up to six processor modules (12 CPUs), up to seven memory modules (28 GiB), up to three I/O modules (12 I/O buses), 1260 MB/s of I/O bandwidth
• AlphaServer 8200: five bus slots, up to three processor modules (6 CPUs), up to three memory modules (12 GiB), up to three I/O modules, 945 MB/s of I/O bandwidth
• Processor modules carry one or two 21164 CPUs at 300 or 350 MHz, or two 21164A CPUs at 440 MHz on the KN7CE module ⁴⁾, each CPU with its own data and address path and a 4 MiB third-level cache on the module
• The minimum configuration is one processor module, one memory module, and one I/O adapter
• Memory modules of 128, 256, and 512 MiB and 1, 2, and 4 GiB, built from SIMMs; modules of 2 GiB and smaller interleave two ways onboard, the 4 GiB module four ways, and two to eight ways between modules
• I/O connects through "hoses" to 12-slot PCI or, on the 8400 only, 12-slot XMI channels; the 8200 supports only PCI buses. ⁵⁾
• The KFTHA I/O port module drives external I/O buses; the KFTIA adds direct SCSI, two Ethernet ports, optional FDDI, and an optional 4 MiB Prestoserve
• Multiple power regulators, optional battery backup, and an optional integrated uninterruptible power supply

The 8200 uses the upper half of the 8400's slot numbering, so its CPU and memory modules sit in slots 8 and higher and its CPUs are numbered from 8, not 0. ⁶⁾

Linux never supported the AlphaServer 8200 and 8400. ⁷⁾ NetBSD runs on them. ^{8) 9)}

Digital announced the 8200 and 8400 in April 1995 as the first systems built on the 300 MHz 21164. ¹⁰⁾ A DEC 7000 could be upgraded to an 8400 in its cabinet by swapping the card cage and centerplane; even the SIMMs from its MS7AA-FA memory modules carried over. ¹¹⁾ A Linux port was started at NASA Ames but abandoned in favor of NetBSD. ¹²⁾

The following sources conflict with each other or with the account given above. They are listed here for further investigation.

• AlphaServer 8400 maximum CPUs
  • AlphaServer 8200/8400 Operations Manual, March 1998, p. 1-7: "up to seven processor modules for a total of 14 CPUs"
  • AlphaServer 8200/8400 Systems Technical Summary, 1996, pp. 2, 5: "Up to 6 CPU modules, for a maximum of 12 CPUs"
  • AlphaServer 8200 and 8400 Windows NT Systems, June 1999, p. 2.4: "maximum of four CPU modules (total of 8 CPUs)"