Dell PowerVault 770N (Deskside NAS Appliance) - Manual (Page 42)

Table 4-1. Expansion Slot Speeds
Slot Bus Operating Speed Signalling Level
1 0 33 MHz 5 V
2 5 33, 66, or 100 MHz 3.3 V
3 5 33, 66, or 100 MHz 3.3 V
4 4 33, 66, or 100 MHz 3.3 V
5 4 33, 66, or 100 MHz 3.3 V
6 3 33, 66, 100, or 133 MHz 3.3 V
7 2 33, 66, 100, or 133 MHz 3.3 V
NOTE: If you are using expansion cards of different operating speeds, you should install the fastest card in slot 7 and the
slowest card in slot 1.
PCI Bus Scan Order
The system's BIOS scans and numbers PCI buses and devices during startup. Expansion slots are scanned according to the
host bus ordering, not by the slot numbers. See Table 4-2 for the order in which the expansion slots and embedded PCI
devices are scanned.
An additional factor affects the assignment of PCI bus numbers: an expansion card may have its own PCI bridge chip which
requires the assignment of a bus number for the card as well as one for the bridge. A particular expansion card may have two
PCI bridge chips which would result in three sequential PCI bus numbers all assigned in the same expansion slot.
If you install expansion cards, you may have some difficulty in directly determining the bus number of a controller on a
particular expansion card. However, the PCI bus scan order listed in Table 4-2 can help determine the relative numbering of
PCI buses within the expansion slots. For example, a PCI controller residing in expansion slot 3 will never have a lower bus
number than one in slot 2 because slot 2 precedes slot 3 in the scan order.
Table 4-2. PCI Bus Scan Order
Order Device or Slot
1 Expansion slot 1
2 Embedded remote access components
3 Video
4 Integrated Gigabit NIC
5 Expansion slot 7
6 Expansion slot 6
7 Expansion slot 4
8 Expansion slot 5
9 Expansion slot 4
10 Expansion slot 3
11 Expansion slot 2
12 Optional integrated RAID controller on the system board
13 Integrated SCSI controller on the system board
Installing an Expansion Card