IBM PC Server 325, User Handbook Manual

Page: 229 / 288

Processor Board Jumpers
Notes:
Ÿ Turn off the server, and disconnect the power cord before
moving any jumpers.
Ÿ Refer to Table 4 on page 216 for the correct clock speed
and frequency selection jumper settings for the
microprocessor. For example, if you have a 200 MHz
microprocessor installed and the system bus speed is
66 MHz (the default), be sure that the jumpers are set to
a bus-to-core ratio 3 (200/66.66).
MHz denotes internal clock speed of the microprocessor
only; other factors might also affect application
performance.
Attention: If the microprocessor bus-to-core ratio is incorrect,
system board components will overheat and component damage can
occur. Be sure that the microprocessor bus-to-core ratio jumper is
set properly.
Table 3 (Page 1 of 2). Defining Microprocessor Operating Parameters
Identifier Default Jumper
Position Description
J1
J20
Clock speed jumper block. The
default setting is 66.66 MHz. Use the
appropriate microprocessor clock
speed for the microprocessor you
have installed.
J30
J29
J28
J27
Frequency selection jumper block.
The default Core/Bus fraction is 3.
J17
J18
Microprocessor memory controller
(PMC) frequency selection jumper
block. The default setting is 66.66
MHz.
Appendix A. Jumpers
215