Ars Technica Motherboard Guide: Part I — motherboard fundamentals
 

The motherboard is perhaps the least glamorous part of the personal computer. Video cards and CPUs all have their die-hard partisans and their benchmark bakeoffs, but a motherboard purchase is less often a matter of fanatical loyalty than it is one of rational cost/benefits/features calculations. Still, the motherboard is the part of the computer that all of the other components plug into, and as the foundation of an upgradable DIY system, it's a choice that demands a certain amount of patient research from the system builder. It's also a choice that has gotten much harder to make in the past two years. The motherboard is actually undergoing something of a Renaissance, as a number of technologies are bringing more bandwidth, more features, and more form factors in more combinations to that central component of any PC system.

The present motherboard guide aims to help the novice system builder make sense of the morass of motherboard options on the market, so that he or she can ask better questions and make more informed choices when shopping for the right motherboard. By the time you're through with this guide, you'll have a solid grasp of the many parts of the motherboard—northbridge, southbridge, processor socket, BIOS, buses, memory, etc.—and of how those parts fit together to make a complete computer. Once you know what all of the most important parts of a motherboard are supposed to do and how they actually do it, then you'll be in a position to understand and to evaluate competing configurations from different motherboard makers

http://arstechnica.com/articles/paed...bo-guide-1.ars

that's a nice guide