DDR SDRAM?

SDRAM means Synchronous Data RAM, runs in synchronism with the clock. DDR also runs in synchronism with the clock but makes two reads/writes per clock cycle, but is very similar memory chip technology.

The full name is actually DDR-SDRAM.

You can give yourself a serious brain cramp if you get too deep into this stuff but anyway.

SDR SDRAM = single data rate Synchronous dynamic random access memory.

This is often referred to as sdram. (cute)

DDR SDRAM = double data rate Synchronous dynamic random access memory. (better/faster)

The confusion comes in when you start seeing terms like

SDRAM
DDR RAM
DDR SDRAM
etc.etc.

This sort of thing is done to keep you on your toes or maybe to throw up you hands and bring the machine to some pc shop and pay them 100 bucks to install the proper memory in the unit.