OFFTEK 1GB Replacement Memory RAM Upgrade for Dell OptiPlex GX520 (DDR2-4200 - Non-ECC) Desktop Memory at Amazon.com
Upgrading Ram in the Dell Optiplex Gx520 - YouTube
NeweggBusiness - DELL OptiPlex GX520 Desktop PC Pentium 4 3.0GHz 2GB 160GB HDD Capacity Windows XP Professional 32-bit 3 Years Warranty for School and Colleges only (Verification Required)
2GB Memory for Dell OptiPlex GX520 DDR2-800 PC2-6400 Desktop DIMM RAM (PARTS-QUICK Brand) at Amazon.com
Dell Optiplex GX520 Mini-Tower: Front Source Tech
DELL OPTIPLEX GX520 NO RAM NO HDD NO OS CHASSIS. REFURBISHED. IN STOCK.