2GB RAM Memory for Dell OptiPlex 780 (Performance Mini Tower ) 240pin PC3-8500 DDR3 DIMM 1066MHz Black Diamond Memory Module Upgrade - Walmart.com
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
Optiplex 780 DT, upgrading ram help - Dell Community
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
1GB RAM Memory for Dell OptiPlex 780 (Ultra Small Form Factor ) 240pin PC3-8500 DDR3 DIMM 1066MHz Black Diamond Memory Module Upgrade System Specific Memory - Newegg.com