The Dell OptiPlex 3060 SFF supports dual-channel RAM with matched SO-DIMMs

Both SO-DIMM slots in the Dell OptiPlex 3060 SFF are user-accessible, and dual-channel is fully supported if you install matched DDR4 modules — 2 x 8GB is the sweet spot. This is a straightforward, no-nonsense memory layout for a small form factor office PC. No soldered RAM, no proprietary modules, just two standard slots and a clear upgrade path.