Dell Dimension U7021 Owner's Manual page 116

Expansion Bus
Bus type
Bus speed
PCI
connector
connector size
connector data width (maximum)
PCI Express
connector
connector size
connector data width (maximum)
PCI Express
connector
connector size
connector data width (maximum)
Drives
Externally accessible:
Available devices
Internally accessible:
116
Appendix
PCI 2.3
PCI Express x1 and x16
PCI: 33 MHz
PCI Express:
x1 slot bidirectional speed - 500 MB/s
x16 slot bidirectional speed - 8 GB/s
four
120 pins
32 bits
one x1
36 pins
1 PCI Express lane
one x16
164 pins
16 PCI Express lanes
two 3.5-inch drive bays
two 5.25-inch drive bays
Serial ATA drive, floppy drive, memory devices, CD drive, CD-RW
drive, DVD drive, DVD-RW drive, and DVD and CD-RW combo
drive
two bays for 1-inch high hard drives