Dell OptiPlex 790 (Early 2011) - Manual (Page 89)

External Connectors
Back Panel: 5
Video 15-pin VGA connector, 20-pin DisplayPort
connector
NOTE: Available video connectors may vary based on the graphics card
selected.
System Board Connectors
PCI 2.3 data width (maximum) — 32 bits
Mini-Tower, Desktop one 120-pin connector
Small Form Factor, Ultra Small Form
Factor none
PCI Express x1 data width (maximum) — one PCI Express lane
Mini-Tower, Desktop, Small Form
Factor one 164-pin connector
Ultra Small Form Factor none
PCI Express x16 (wired as x4) data width (maximum) — four PCI Express lanes
Mini-Tower, Desktop, Small Form
Factor one 164-pin connector
Ultra Small Form Factor none
PCI Express x16 data width (maximum) — 16 PCI Express lanes
Mini-Tower, Desktop, Small Form
Factor one 164-pin connector
Ultra Small Form Factor none
Serial ATA
Mini-Tower four 7-pin connectors
Desktop, Small Form Factor three 7-pin connectors
Ultra Small Form Factor two 7-pin connectors
Memory
89