OFFTEK 512MB Replacement Memory RAM Upgrade for Dell OptiPlex GX620 Series (Desktop Mini-Tower and Small Form Factor) (DDR2-4200 - Non-ECC) Desktop Memory at Amazon.com
Best Buy: CMS 2GB (2x1GB) RAM Memory Compatible with Dell OptiPlex GX620 DT / MT / SFF Desktop CM128645300DIMMX2001