Processor Upgrading; Ycle - HP Deskpro EX Technical Reference Manual

Chapter 3 Processor/Memory Subsystem

3.2.3 PROCESSOR UPGRADING

3.2.3.1 Physical Considerations In Upgrading
All units use the PGA370 ZIF mounting socket and ship with either a Celeron or a Pentium III
processor in a Flip-Chip (FC-PGA370) package installed with a passive heat sink.
CAUTION: These systems are specifically designed for processors using
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the FC-PGA370 package. Other processor packages (such as the PPGA370 package)
will physically fit the socket but are not compatible due to electrical and thermal
issues.
The FC-PGA370 package consists of the processor die mounted "upside down" on a PC board.
This arrangement allows the heat sink to come in direct contact with the processor die. The heat
sink and attachment clip are specially designed provide maximum heat transfer from the processor
component.
CAUTION: For proper heat dissipation, attachment of the heat sink to the processor is
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critical on these systems. Improper attachment of the heat sink will likely result in a
thermal condition. Although the system is designed to detect thermal conditions and
automatically shut down, such a condition could still result in damage to the processor
component. Refer to the applicable Maintenance and Service Guide for detailed
processor installation instructions.
Upgrading the processor may require the connection of a power cable from the processor's
heatsink-mounted fan to a header on the system board.
The processor core voltage and operating frequency are automatically set early in the power cycle
process. No DIP switch settings are involved in replacing the processor.
3.2.3.2 Software Considerations In Upgrading
Although the Celeron and Pentium III processors are software-compatible, it is recommended that
the replacement processor be either of the same family as the existing processor (i.e., Celeron for
Celeron, or Pentium for Pentium) or an upgrade (Pentium III for a Celeron). A "downgrade"
(going from a Pentium III to a Celeron) may result in problems with resident software that has
been "tuned' to take advantage of the Pentium III processor's special features (such as SSE
instruction execution). This is more of a concern with systems running Windows 98 and NT.
3-4 Compaq Deskpro EX Series of Personal Computers
First Edition - August 2000