Chassis Similarities; Standard Features; Pentium Ii Microprocessor; Secondary L2 Cache - Dell OptiPlex GXa Service Manual

C
hassis Similarities
All four chassis configurations have the following similarities:
•
Use the same system board (OptiPlex GXa systems can use either the stan-
dard or EM system board; the OptiPlex NX systems use the EM system
board)
•
Identical operational characteristics (same BIOS, POST, memory,
microprocessor, external I/O ports, and so on)
•
Identical diagnostics, diagnostic beep codes, and diagnostic-screen error
messages (see Chapters 1 through 3 and Appendix A). However, the
OptiPlex NX computer has no built-in diskette drive and requires a special
setup to run diskette-based diagnostics as described in Chapter 2.
S
tandard Features
The features described in the following subsections are common to all chassis
configurations. However, some of the features differ slightly, depending on
which version of the system board is installed (standard or enhanced manage-
ability version). Where differences occur, they are marked in the paragraph
titles.

Pentium II Microprocessor

All systems in the OptiPlex GXa and OptiPlex NX computer families incorpo-
rate the Pentium II microprocessor for improved operating speeds and overall
performance. Some of the major enhancement features of the Pentium II micro-
processor include internal 16-KB data and instruction caches, internal math
coprocessor, and the MMX instruction set for high performance in complex
multimedia and communications environments. The Pentium II microprocessor
also uses a technique called Single Instruction, Multiple Data (SIMD), which
permits processing data elements in parallel for additional system performance
enhancement.
The microprocessor is physically located in a single-edge contact (SEC)
cartridge/heat sink assembly on the system board for ease of upgrading when
faster processors are available. Contact Dell Computer Corporation for informa-
tion about Dell-supported microprocessor upgrades.

Secondary L2 Cache

For additional performance, the OptiPlex GXa and OptiPlex NX systems
employ a secondary cache memory subsystem with a cache memory controller
and 512 KB of pipeline-burst SRAM cache memory. The L2 cache SRAM is
located in the SEC cartridge/heat sink assembly on the system board.
System Overview 1-3