Question Regarding Processor Type

Go for one of the systems with a Pentium-M procssor (Inspiron 8600, 600M, etc.).  The P4-mobiles are in the Value systems (1150/5150) which don't have the best reliability reputation.  The 9100/XPS uses a desktop P4 for all-out performance - but they're bulky, heavy and don't run long on battery.

 

The previous post is correct in describing the processor types. I would also suggest a Pentium-M (keep in mind this is not the same thing as a Pentium 4-M). The Pentium-M is the most mobile processor intel makes and is a very good processor. If you are planning to take your laptop home or to class often, then a Pentium-M is the way to go. The Pentium 4-M are being used less and less now since the Pentium-M has equal performance and runs cooler and on less power. The Pentium-4 is a desktop processor so when used in a laptop it has very good performance, but terrible battery life and lots of heat. Only get one of these if you don't plan to move the laptop often. Your final processor option is the Celeron, avoid this like the plague. It is a cheap processor and will make your life painful.