QuoteThe T43 2xxx is supported by APM, and that's what makes those machines special
I don't know about "special". It does seem that the T43 2xxx series does support ACPI. Possibly APM too (I don't know for sure). You can use the ACPI utilities SETGETSTATE and SETGETTHRTL to determine if the machine supports those functions (you do need ACPI loaded to do the tests). If it does, you can use them to reduce power consumption, which also reduces heat output, and extends battery life.
My old Coolman prototype used both of those, when they would work, but REXX and external programs, are really too limited to be really effective. I found that SETGETSTATE did more to reduce power consumption than SETGETTHRTL does. The new ACPI power management appears to use throttling, but not the STATE settings. I am not sure exactly what throttling does, but the STATE settings reduce the machine clock speed, which lets the hardware work with less power consumption, but it is slower. The new ACPI has added a new twist, that I never thought of (probably because I was working with a single core machine), and that is to turn off all but one core of a SMP machine. Now, they have also added the use of the HLT command, to further reduce power consumption. Of course, with all of these methods, there needs to be a way to speed it up when the power is needed, and slow it again when the demand is not there. ACPI, using throttling, core reduction, and HLT, seems to work great on SMP machines, but it is far less effective on single core machines. You can effectively measure the effectiveness of these techniques by monitoring the system temperature. For example, my Asus M3A78-EM, with quad core Phenom processor, runs at about 59C (138F), with no power control. With throttling, it runs at about 55C (131F). When it uses throttling, and core reduction, it runs at about 42C (107F). Add HLT , and it runs at about 38C (100F). While the machine claims to have two STATE settings, SETGETSTATE cannot change them, for some reason (although, I haven't tried that with the new ACPI).
My IBM ThinkPad T43 (1871-W8M - single core), runs at about 72C (161F) with no power control. With throttling only, it runs at about 62C (143F). Add HLT, and it runs at about 58C (136F). Of course, core reduction is not possible with a single core machine, so that is what ACPI can do for it. Now, if I use SETGETSTATE to set it to the slowest clock speed, it runs at about 42C (107F). The battery life is extended with each step too, and, of course, the T43 doesn't cook your legs, if you use it on your lap, until you run a program that speeds it up for more than a few seconds. :)
My Lenovo ThinkPad T510 (dual core, running with hyperthreading enabled - contrary to suggestions in the ACPI package), runs at about 62C (144F) with no power control. Throttling knocks it down to about 52C (125F), core reduction goes to about 48C (118F), and HLT goes to about 43C (109F). SETGETSTATE does not work. Note that I use hyperthreading because it makes Win7 work MUCH better. It doesn't seem to do much (good, or bad) for eCS, so I just leave it enabled.
Of course, suspend/resume is not usable with any of them. On the other hand, I have an antique IBM ThinkPad A22e that has full APM support, and it does suspend/resume, and hybernation (full power off, with very quick recovery), with no problem (the BIOS actually does it, with a little support from the OS). It does not do power reduction though. It has no support for ACPI, and it will cook your legs if you use it on your lap.