8GB Kit (2 X 4GB) DDR3 Memory Upgrade for Dell OptiPlex 780 Small Form Factor Desktop PC PC3-12800 240 pin 1600MHz RAM (PARTS-QUICK Brand) at Amazon.com
4GB [2x2GB] DDR3-1333 (PC3-10666) RAM Memory Upgrade Kit for The Dell Optiplex 780 Desktop (Genuine A-Tech Brand) at Amazon.com
Dell Optiplex Memory | RAM Upgrades
780 SFF, ram upgrade - Dell Community
MemoryMasters 4GB DDR3 1333MHz PC3-10600 Non ECC Unbuffered 1.5V CL9 Dual Rank for Dell Optiplex 780 DT/MT/SFF Memory Ram Upgrade and More (Low Density 4GB) - Walmart.com
Tried upgrading optiplex 780 ram, wont turn on - Dell Community