RE: Upgrading Ram in a Inspiron 530s?
4gb is the maximum.
The Foxconn G33m02 [Dell P/N ORY007] motherboard that is the default motherboard installed in the 530s Slimline, supports a maximum of 4gb of DDR2 RAM.
The Foxconn G33m03 [Dell P/N OFM586] motherboard can support 8gb [4 x 2gb modules].
Plus you will need a 64-bit operating system.
The Inspiron 530s is probably not worth upgrading, used 530s can be purchased for $100/125 off eBay.