Confusion with processors

I don't think I'd recommend any of them for embedded use...

Except for a toaster, or maybe an indoor grill.

Pentium D(Dual Core) - stop gap attempt at a dual core processor after AMD caught them flat footed. Had a horrible memory interface and poor performance

Core2 Duo - second attempt with a more reasonable memory interface

Core2 Quad - 2 Core2 Duo in a single package to beat AMDs real quad core chip due later this year, again a bit of a memory interface kludge (now you know why intel chips have an obscene amount of cache)

Core2 Extreme - no idea but sounds expensive.

The "extreme" chips have more cache and allow overclocking.

Core, here, means processor core (i.e. processors). The Pentium D has two Pentium4-class processors inside. The Core2 Duo has two Core2-class processors inside. The Core2 Quad has four processors inside but the current implementations are two Core2 Duo *chips* in one package. ALU's are a complete red herring. The Extreme processors are just the top end versions sold typically for gaming, where overclocking is the norm and valiant efforts to keep things cool enough are part of the 'fun'.

Pentium4-class processors are effectively obsolete, with all new devices being Core2 based. The Pentium 4s clock faster and use much more power but delivr inferior performance in most situations. Each Pentium 4 core can execute up to 3 instructions per clock while each Core 2 core can execute up to 4. The key here is 'up to' and how close they get to that peak performance.

Peter