Buying a laptop isn't as straightforward as it would seem. There are far too many variables and not enough understandable information. The goal of this entry is to clarify some of the confusion. I am sure this will be out of date, as soon as I submit it.
I suppose the most important question is why are you buying the laptop? In my case, I am looking for a fairly powerful machine for application testing, which means that it needs to be able to handle installs (and removals) of a wide variety of software packages for data analysis, simulation and the like. I also want something with good capability for working in cafe's or while traveling. Today, this translates into wireless capability with at least five hours battery life. I don't particularly need super graphics, because my clients aren't going to be in that market. Oh, and did I mention I would like a somewhat attractive machine, instead of a grey or black brick?
The first requirements I find fairly easy to comprehend. I want a fast processor, at least 512 MB (fast) RAM, and at least 40 GB of (fast) hard disk space.
The mobile requirements throw a wrench in the equation, primarily because of the confusion Intel has created with their Centrino and Pentium-Mobile technology names.
It takes a while to find it, but there are a bunch of Intel "mobile" processors, all of which are supposed to use less power than their desktop counterparts: Pentium M (aka "Centrino," previously "Banias"), Mobile Pentium 4 (with hyperthreading), Mobile Pentium 4-M, and Mobile Celeron which are the current-available processors. They have also sold a variety of other mobile processors: Mobile Pentium II, Mobile Pentium III, and Celeron-M. It doesn't help that Intel's own website isn't really clear on all of this. Here's Intel's Processor Specs page, if you are curious.
The thing that really helped me was discovering that there really is more to Centrino beyond the marketing hype. To be tagged "Centrino," a machine must have three things: the Mobile Pentium-M (Centrino) processor, the power-lite Intel 855 chipset, AND the integrated 2100 (802.11b) or 2100a (802.11a/b) wireless card. It isn't as heavily advertised, but the wireless card appears to come with integrated Bluetooth capability, which would be a nice bonus for me with a Bluetooth-enabled PDA. The other exciting thing to know about the Centrino processor is that it, apparently, runs more floating point operations per second (flops) than ostensibly faster Mobile Pentium 4 processors. PCWorld reported this in a March 2003 article, First Tests: Intel's Centrino. Their benchmarks clocked 1.6GHz Centrino notebooks at 10-15 percent faster than 2.4GHz Pentium 4 machines.
There is also the Intel Mobile designation for laptops / notebooks, which means that the computer contains one of the mobile processors and its low-power chipset (see Intel's processor roadmap). These machines DO NOT have the integrated wireless card, which Intel believes is the most efficient setup, but most are being sold with a separate wireless card.
What this means is that any Centrino or Mobile laptop should do the trick for me. I'll just need to decide whether I can live with 802.11b in a "Centrino" machine, or if I want to have the latest 802.11g wireless in a "Mobile" machine. The only other watchout is the type of battery - I'll need to be sure to find a long-life battery to get the reported 5-7 hours of life on these machines.
General costs on Mobile and Centrino lines are discussed on another set of Intel roadmap pages: Centrino, Mobile P4-M. They seem to be compatible with what I've seen while shopping the net. The price varies heavily with other features I want to add to the machines. For instance, jumping from 512MB to 1GB of RAM adds $800 in one case.
All that's left is finding an attractive laptop that has all these pieces in one "pretty" package.