Dell OptiPlex 990 (Early 2011) - Manual (Page 98)

System Board Connectors
Mini PCI Express data width (maximum) —
one PCI Express lane and one USB
interface
Mini-Tower, Desktop,
Small Form Factor none
Ultra Small Form Factor one 52-pin connector
Serial ATA
Mini-Tower four 7-pin connectors
Desktop three 7-pin connectors
Small Form Factor three 7-pin connectors
Ultra Small Form Factor two 7-pin connectors
Memory
Mini-Tower, Desktop,
Small Form Factor four 240-pin connectors
Ultra Small Form Factor two 240-pin connectors
Internal USB
Mini-Tower, Desktop one 10-pin connector
Small Form Factor, Ultra
Small Form Factor none
System Fan one 5-pin connector
Front panel control
Mini-Tower, Desktop,
Small Form Factor one 34-pin and one 5-pin connector
Ultra Small Form Factor one 20-pin and one 14-pin connector
Thermal
Sensor Mini-Tower one 2-pin connector
Desktop, Small Form
Factor, Ultra Small Form
Factor two 2-pin connectors
98