Dell OptiPlex 790 (Early 2011) - Manual (Page 9)

Memory
Memory module connectors
Desktop, Mini-Tower, Small
Form Factor four DIMM slots
Ultra Small Form Factor two DIMM slots
Memory module capacity 1 GB, 2 GB, and 4 GB
Type DDR3 1333 MHz
Minimum memory 1 GB
Maximum memory
Desktop, Mini-Tower, Small
Form Factor 16 GB
Ultra Small Form Factor 8 GB
Drives
Externally accessible:
5.25 inch drive bays
Mini-Tower two
Desktop one
Small Form Factor one slim optical drive bay
Ultra Small Form Factor one slim optical drive bay
Internally accessible:
3.5 inch SATA drive bays
Mini-Tower two
Desktop one
Small Form Factor one
Ultra Small Form Factor none
2.5 inch SATA drive bays
Mini-Tower two
Desktop one
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