T42 is last IBM-designed T laptop, I am told. T43 is a lenovo design. IBM thinkpads running Plan 9 run HOT, as least mine do. They also run hot running Xen. Seems like ACPI really matters.
We fixed a T23 here by cracking it open and putting good heatsink paste on the CPU. Our T23 had same symptoms as yours; all went away with the re-application of heatsink paste. Generally, the CPUs turn themselves off before real damage is done (nowadays). ron
