OFFTEK 2GB Replacement Memory RAM Upgrade for Dell OptiPlex 755 Series (Desktop Mini-Tower and Small Form Factor) (DDR2-6400 - Non-ECC) Desktop Memory at Amazon.com
i found this dell optiplex 755 in a scrap yard perfectly functioning{came with side panel just have it off} its ungodly slow with only a single stick of ddr2 2gb ram and
8GB 4X2GB Dell OptiPlex 755 Series Desktop/PC DDR2 PC2-5300 RAM Memory at Amazon.com
Restored Dell Desktop Computer Optiplex 755 Intel Core 2 Duo Processor 4GB RAM 250GB HDD DVD 19" LCD Monitor - Windows 10 PC (Refurbished) - Walmart.com
Refurbished: Dell Optiplex 755 Small Form Factor Desktop (R2/Ready for Reuse) with Intel Celeron 430@1.80GHz, 2GB RAM, 80GB HD and licensed Windows 7 Home Premium from a Microsoft Authorized Refurbisher - Newegg.com
Dell Optiplex 755 PC Computer Tower Windows 10 Professional (Win 10) 4GB RAM 250GB
Refurbished: Dell Optiplex 755 Small Form Factor Desktop (R2/Ready for Reuse) with Intel Celeron 430@1.80GHz, 2GB RAM, 80GB HD and licensed Windows 7 Home Premium from a Microsoft Authorized Refurbisher - Newegg.com
Dell Optiplex 755 SFF Core 2 Duo 2.33 GHz - HDD 1 TB RAM 4GB | Back Market
Dell Optiplex 755 Desktop PC 4GB RAM, 128GB Solid State Drive + 2TB HD – RefurbishedPC