8GB (2x4GB) Memory RAM fits Dell OptiPlex 5040 Small Form Factor, 5040 MT A76 | eBay
Amazon.com: A-Tech - Memoria RAM de 8 GB para Dell OptiPlex 5040 SFF, DDR3L, 1600 MHz, PC3-12800, no ECC, DIMM 2Rx8, 1,35 V, módulo de actualización de escritorio único (repuesto para A8733212) : Electrónica
Dell OptiPlex 5040 SFF Computer 6th Gen i5 | 8GB RAM 256GB SSD Windows – My Tech Lifestyle
Refurbished Dell OptiPlex 5040 Small Form Computer Desktop PC, Intel C – Dealsoutlet