I have a Dell Inspiron 530 with the 0RY007 motherboard. I looked at the spec before I bought any new RAM and it says it supports 4 x 240-pin Dual Channel DDR2 800/667 MHz non-ECC, un-buffered memory (Max 8GB). In my BIOS it says:
Memory Installed - 7168MB
Memory Available - 3327MB
Memory Speed - 800MHz
Memory Channel Mode - Dual
Memory Technology - DDR2 SDRAM
I have installed:
3 PNY 2GB DDR2 PC2-6400 @800MHz
1 Elpida 1GB DDR2 PC2-6400 @800MHz