Glad to be of help
- Celeron M lacks Speedstep, and thus probably have very limited under-clocking/volting possibilities especially since laptop BIOSes are spartan to say the least. Speedstep must also be supported by the chipset, which Intel desktop chipsets of that generation did not (as I found out by swapping a P4 with a P4-M into a desktop replacement i845 Toshiba - it was stuck at 12x100MHz, no idea about the voltage provided). All Pentium M support Speedstep, low voltage or not.
- Speedstep on Pentium M yields an idle speed of 600MHz at a lower voltage, and a plugged-in/full speed state running the CPU at its rated speed. Not sure whether intermediate multipliers are used by the XP default driver or the OEM W2K Speedstep software. However, utilities such as RMClock give full access to the intermediate multipliers, as on the latest generation AMD and Intel CPU's. No FSB fiddling, that would be in the BIOS, and major manufacturers won't support such a feature.
- there actually is a good wiki on Pentium M's with all the info you need: http://en.wikipedia.org/wiki/List_of_In ... processors
- I believe the lowest VID a Pentium M can request is 0.700V, but am not sure if that applies to all machines; my Portege M100 idles stably at that voltage.
- as for the minimum voltage a CPU will run at at a given frequency, it is a matter of trial and error for every individual CPU. For my P-M 1.2GHz, the linear interpolation offered by RMClock turned out to be suitable. Some of my CPU's (especially my 65nm Athlon X2) tend to crash upon VID/FID changes when running close to their lower voltage limits; RMClock has an option to up the voltage momentarily during transitions to address that. Also, on a LV/ULV P-M, the processing power difference between various multipliers isn't great, so in practice the CPU will run at 600MHz when idle, and at maximum speed when in use. I've only activated the 6x, 9x, and 12x multipliers on my M100, and the 900MHz setting is hardly ever called upon. In other words, no need to activate all intermediate multipliers with the resultant (potentially stability-affecting) frequency/voltage hopping.
- most Banias laptops accept a Dothan with a BIOS update. Since it was a minor refresh, many makers just used the same motherboard on their Dothan machines, with the aforementioned BIOS update. Check on specific models on their manufacturers' websites; the readme for a BIOS sometimes mentions something like 'support for Dothan CPU' (Toshiba's updates do).
- makers are very coy about their use of a 1.8" HD... if the top-of-the-line version of a T&L came with a 20 or 30GB HD, there is a good chance it was a 1.8". The 60GB 1.8" came out much later in the Pentium M lifecycle, and is more likely to be found on Core Solo ULV machines.
- you'll have to google about to ascertain which subnotes have 1.8" HD. To my knowledge, only the Panasonic Let's Note R3 and later (I think R3, perhaps also the R2) use 2.5" HD, among the 2lbs class machines. Users on this forum seem to care about that issue: http://www.leog.net/fujp_forum/default.asp
. However I have no idea about what IBM/Dell/etc were doing at the time, since I was never interested in their subnotes (my theory is that American hands are too big for a 2lbs subnote's keyboard...)
- the temperature at which the CPU fan is activated fully depends on the individual laptop's BIOS and sensor. I haven't found any 3rd party software to influence this. You'd be surprised at how frequently some subnotes can run their fans, e.g. even at idle if resting on a non-heat conducting surface.
- my Panasonic CF-S51's original 266MHz CPU was rated at 9.8W, the 400MHz one at 13.1W. Fan runs more often than I'd like, but the shim definitely improved things. Those machines used 'mini-cartridge' Pentium II's (probably born because early mobile PII's did not have an on-die cache), which were later ditched for space and cost reasons. Check here for individual processors' specs: http://processorfinder.intel.com/
Panasonic Let's Notes have a strong following on ebay.co.uk... Some pop up from time to time on the Singapore site (people in SIN and HKG love Japanese toys...). If you have an opportunity to source from Japan, take a look at http://kakaku.com/used/search.asp
Navigate around the japanese menus by reading the links ; you'll get an idea of the going used prices for those machines, in a market not distorted by constricted supply (early 900MHz P-M Let's Note R2 start around $380). I'm thinking of picking one up next time around...