Could anyone explain 'yields' to me?

[Goose]

I've been meaning to ask this for ages but i've never actually educated myself on the manufacturing of computer chips. I've overclocked for years and accepted that not all chips are as good as each and my question really is why?

What causes yields to be low/high and why is there such a variation in the quality of the chips? To a noob like me producing computer components seems like such precise science that everything produced should be exactly the same

I'm not expecting anyone to write and essay for me, just a simpletons explanation (or a link to one) would be super.

Thanks

 

[Rroff]

http://forums.overclockers.co.uk/showpost.php?p=27623966&postcount=6

There was some replies later in that thread http://forums.overclockers.co.uk/showpost.php?p=27625594&postcount=28

 

[SiDeards73]

http://www.techradar.com/news/computing-components/graphics-cards/how-gpus-are-made-1000923

Old article but i think its still relevant

 

[Goose]

http://forums.overclockers.co.uk/showpost.php?p=27623966&postcount=6

There was some replies later in that thread http://forums.overclockers.co.uk/showpost.php?p=27625594&postcount=28

Thanks, don't know I managed to miss the replies, I must have given up checking too easily.

http://www.techradar.com/news/computing-components/graphics-cards/how-gpus-are-made-1000923

Old article but i think its still relevant

Ta muchly.