I came across a wonderful Computer Hardware Review site - XBit Labs. Contains in-depth information on a wide range of hardware products, right from motherboards, graphic cards, RAM's to CPU fans, Strage devices etc ...

http://www.xbitlabs.com/

One good interesting article was about the basic difference between DDR and DDR2 memory.

http://www.xbitlabs.com/articles/memory/display/ddr2.html