Like most others already said, the Pentium M gives very good performance compared to it's clockspeed (and again compared against other Intel CPUs). Not all tasks benefit from the larger caches, but on an average, one could state the Pentium M performs like a 800~1000Mhz faster P4 machine.
Batteries aren't drained that fast anymore. At least, what the CPU is concerned. When making use of other draining parts of the system (GPU -gaming- or WLAN), your battery can still be depleted within 1.5h. It also depends on the capacity of the battery of course.
For desktops I think that the AMD Athlon 64 series are the better choice. They give good performance and generate less heat than the modern P4 CPUs. You say less? Yes, they do! The modern P4s have a much higher TDP than the Athlon 64 CPUs. The story about AMD CPUs having a shorter life is what I'd call nonsense. Of course, excessive heat production isn't that good for CPUs, but when cooled well it's not a single problem. BTW: Athlon 64 CPUs are fitted with a technology called "Cool 'n quite
". This means that when the CPU doesn't have anything to do, it lowers the clockspeed, yielding a cooler and less noisy system.
If you think that I'm an AMD fanboy, you are correct :). On the other hand, I have to be as honest and objective as possible and tell you the benefits of the Intel CPU.
Intel CPU's have a speedtrotthling technology. If your cooling fails, the CPU can't get damaged, it just lowers it clock speeds. AMD CPUs can't do this. Instead, they can get damaged (in practice this never happens; they only crash and require a reboot).
The P4 also supports hyperthreading: this technology can make the OS think that there are two CPUs present. Is that a good thing? It can be. When you're using software that was designed for using HT, it can up your performance up to 30%. However, if the software wasn't designed for HT, you can loose 30% of the performance!
Than there's the broader SSE support. These instructionset enhanchments by Intel can give some extra performance, when using software that was written to handle it.
Also some newer technologies like PCI-e, SLI and DDR2 are (better) supported on the Intel platform.
In practice, it comes to this:
- General use: Intel and AMD (I prefer AMD because of cool 'n quite)
- Adobe products: Intel (AMD will get better at this soon, because of better SSE and 64bit support)
- Gaming: AMD
- Video encoding: Intel is slightly faster, but that will be changing as soon as 64bit is fully supported
- Other computational tasks: AMD wins in most cases
I've been using AMD CPUs for 6 years now. I think I had over 15 CPUs (no I didn't wear them out, I just sell my when I get the chance to) and I'm very happy with them. Most overclock pretty well, perform good, don't cost too much and run like a charm. My first AMD (a K6-2) still works and is running on 433Mhz (it was designed for 300MHz!). And those CPUs were considered to be crappy .
Intel makes good stuff (good quality) but can't keep up with AMD on some points. For me (and to many others as well) these points are quite important.