NEC 1080Xd - Manual (Page 178)

5-6 I/O Board Installation
Selecting a Slot
Installation can impact the operating frequency of a board. Note the following
information before selecting a PCI slot:
Note: See Figure 5-2 for Core Module slot locations or
Figure 5-4 for PCIX Unit slot locations. These figures slot
frequencies and bus groups.
The actual operating frequency of a board is lower than the highest specified
operating frequency when the following conditions occur:
! More than two PCI boards are installed in the same bus group (does not
apply to PCI-X boards)
! Boards with different operating frequencies are installed in the same bus
group.
PCI 33-MHz is the highest specified operating frequency for the following
boards:
! Basic I/O Board
! SCSI Card DAT device in the server chassis.
See Table 5-3. for information about how installation in a particular slot and
with other boards can determine the operating frequency of boards within the
bus group.
Table 5-3. Board Installation and Operating Frequencies
Board Type Installation Operating Frequency
PCI 33-MHz
board Installed within the same bus group with other
boards having a higher operating frequency than
33-MHz Operating frequency of all boards
is 33 MHz.
PCI 66-MHz
board Up to 2 boards installed within the same bus group
Three or more boards installed within the same bus
group
Operating frequency of boards is
66 MHz.
Operating frequency of all boards
is 33 MHz.
PCI-X 66-MHz
board All slots within the same bus group are occupied
with PCI-X 66-MHz boards Operating frequency of all boards
is 66-MHz.
Operating frequency does not
decrease as in PCI examples.
PCI-X 133-MHz
board Installed in 66-MHz slot Operating frequency is limited to
66 MHz; installation in 66-MHz
slot is not recommended.