Specifications

9 March 1999 – Subject To Change Introduction 1–3
System Components and Features
1.1.1 21174 Core Logic Chip
The Alpha 21164 microprocessor is supported by the 21174 core logic chip, which
provides an interface between three units—memory, the PCI bus, and the 21164
(along with flash ROM). This core logic chip is the interface between the 21164
microprocessor, main memory (addressing and control), and the PCI bus.
Sixteen quick switches provide the memory interface data path.
The 21174 includes the majority of functions necessary to develop a high-perfor-
mance PC or workstation, requiring minimum discrete logic on the module. It pro-
vides flexible and generic functions to allow its use in a wide range of systems.
1.1.2 Memory Subsystem
The synchronous dynamic random-access memory (SDRAM) is contained in two
banks of dual inline memory modules (DIMMs). Single- or double-sided DIMMs
may be used. Each DIMM is 72 bits wide, with 64 data bits and 8 check bits, with
100 MHz or faster speed. Two DIMMs provide 32Mb to 256MB of memory, while
four DIMMs provide up to 512MB. Table 1–1 lists the DIMM sizes tested and the
corresponding main memory size for 128-bit arrays
Table 1–1 AlphaPC 164LX SDRAM Memory Configurations
Bank 0 Bank 1
Total Memory J8 J9 J10 J11
32MB 2Mb X 72 2Mb X 72 ——
64MB 2Mb
X 72 2Mb X 72 2Mb X 72 2Mb X 72
4Mb
X 72 4Mb X 72 — —
96MB 4Mb
X 72 4Mb X 72 2Mb X 72 2Mb X 72
128MB 4Mb
X 72 4Mb X 72 4Mb X 72 4Mb X 72
8Mb
X 72 8Mb X 72 — —
160MB 8Mb
X 72 8Mb X 72 2Mb X 72 2Mb X 72
192MB 8Mb
X 72 8Mb X 72 4Mb X 72 4Mb X 72
256MB 8Mb
X 72 8Mb X 72 8Mb X 72 8Mb X 72
16Mb
X 72 16Mb X 72 — —
512MB 16Mb
X 72 16Mb X 72 16Mb X 72 16Mb X 72