DDR stands for Double Data Rate, which in itself means little to the non tech person. The thing to remember is that DDR1, DDR2 and DDR3 are all incompatible with each other. The tiny U shaped cut in the memory card is in a different location on each and a laptop using DDR3 cannot be fitted with the others. DDR3 is the fastest memory chip of them all; uses less power and is the most efficient. If you want to increase the memory on your laptop,you first need to find out which chip it requires. On Samsung laptops, memory is usually located on the underside and all it needs is to unscrew the only screw and the DDR version is written there. If not, look at the chip and have a look on a search engine to find out which one it is.
This particular one is a reliable brand and installing this to replace a 1GB chip does small wonders. At this price, if you are running Win 7 on 1GB, it really is worth getting this 2GB chip. Most laptops have just one slot for a memory chip, so the existing 1GB chip becomes redundant which is a shame but can't be helped.