Use this guide to upgrade the RAM in your 2006/2007 20" iMac to a maximum of 2GB (1GB x2)
iMac 2006/2007 20" RAM Upgrade Guide (iMac4,1 and iMac5,1)
Use this guide to upgrade the RAM in your 2006/2007 20" iMac to a maximum of 2GB (1GB x2)