Originally Posted by Faster_is_better
What are those ASIC miners made from? Are they just a specialized processor or what?
Precisely. They are custom silicon which only handles instructions necessary for bitcoin mining. They are mostly vaporware so I wouldn't buy one if I were you. Here is a quick summary of ASIC's vs GPU's for mining:
Faster than anything out there $ for $
Use less power per hash
Some manufacturers (such as Butterfly Labs) might actually be scams, or at the very least, might not ever successfully ship a product.
Since they are custom silicon made for coin mining, they have no resale value if the currency fails
Can be used for other awesome things such as gaming, F@H, etc.
They use almost precisely as much power as they return in coin currency, so you might not be making any profit at all.