![a DDR2 chip](https://www.dvhardware.net/news/elpida2gbddr2_23062005.jpg)
Here is a snippet: All DDR2 chips use BGA (Ball Grid Array) packaging, while DDR chips almost always use TSOP (Thin Small-Outline Package) packaging. There are DDR chips with BGA packaging on the market (like the ones from Kingmax), but they are not so common. Read more at HardwareSecrets