OT: ThinkPad vs Inspiron

Yes, another laptop question unfortunately.

Dingly ding. We've all got IBM ones which allegedly work, but they seem
flaky at best.

I've used them to hook up a GPS and a friend's ancient plotter to their
new PC. Not had problems so far.

I tried to use one[1] with my Power Commander, & it wasn't having none
of it.

[1] Waves at Gyp.

I'm replacing my current Dell with something lighter and with a longer
lasting battery. One of the niggles I have with the current Dell is the
variable fan kicking in to cool the CPU.

I figured with the Dual Core, it needs less power so shouldn't get so hot,
and therefore will run quieter. That's where a new Inspiron 640m comes
in. It has all I want at a pretty cheap price. Are these new boxes
quieter?

However, some negative comments about build quality lately got me looking
elsewhere, and a ThinkPad T43p looks rather tasty with a good quality
screen, light weight, good battery and the darsy-amusing accelerometer.
Question is, does the Pentium M require cooling with a noisy fan?

I can recommend the Core 2 Duo. We've got a batch of Dell Latitude D620
with it and the battery life seems to be about 5 times the D610 with
Pentium M. Seems to run quiet most of the time but the fan does kick in
occassionally.