Designator
Name on board
Component
SW3
Rear Power Switch
Rear power button/LED
SW50
CMOS
Clear CMOS button
XBT1
BAT
Battery
XMM1
CPU0-DIMM8
CPU0 Memory DIMM8
XMM2
CPU0-DIMM7
CPU0 Memory DIMM7 (not loaded on Z640)
XMM3
CPU0-DIMM6
CPU0 Memory DIMM6
XMM4
CPU0-DIMM5
CPU0 Memory DIMM5 (not loaded on Z640)
XMM5
CPU0-DIMM1
CPU0 Memory DIMM1
XMM6
CPU0-DIMM2
CPU0 Memory DIMM2 (not loaded on Z640)
XMM7
CPU0-DIMM3
CPU0 Memory DIMM3
XMM8
CPU0-DIMM4
CPU0 Memory DIMM4 (not loaded on Z640)
116 Appendix C System board designators