GPU/CPU questions

[Pixie]

1. We're all familiar with the GPU's and southbridge's flexing issue, which can be temporarily solved by applying pressure to said chips while booting. How can it be, though, that it suffices to press only during boot, for just a few seconds, and the laptop can then run on for hours? Why is the pressure not needed anymore? Doesn't the chip start immediately to wander off after cessation of pressure?

2. I've noticed that our GPUs (ATI) don't have a heat sink, as opposed to other laptop. Is this correct? Don't our GPUs suffer from overheating? (My own GPU, which currently probably suffers from flexing, feels quite hot to touch, and this only after a few minutes after turning on. Is this normal?)

3. While we're at it, is it required to once in a while disassemble the CPU and apply thermal paste, as should sometiems be done with desktops? There's no CPU temp indicator in the BIOS, incidentally. Should I install a third-party diagnostic software for that? How frequently does a Thinkpad T40 suffer from overheated CPU?

[dr_st]

1. I assume it depends on the nature of failure and how far it progressed. It is possible that during power-up the chip goes through various quick test to verify it's fully functional. If even one of them fails, it will lock up and refuse to continue. However, during normal operation, some of these paths (which may be faulty) may not be used, except in very specific scenarios. This would explain why, if pressure tricked the device to pass the power-on tests, the laptop can function normally for a long time.

2. Some do, some don't. The ATI 7500 boards do not, presumably because the chip is considered less power-hungry / hot. The ATI 9600 / FireGL boards use the long heatsink which covers the GPU. AFAIK, it is possible to mount the long heatsink on the 7500 board, as an aftermarket solution, which may (although not consistently) improve the longevity of the chip.

3. It is not required, per se, not with desktops, nor with laptops. With that said, not all thermal compounds are created equal. Some, even after years, do not dry up and continue performing just as well. Others do dry up and become less effective. AFAIK, the stock white compound used by default on genuine Thinkpad heatsinks, unfortunately, happens to be of the latter, poorer quality. "Refreshing" aside, many forum members will tell you that better cooling performance can be achieved by replacing it with better paste (Shin-Etsu, Arctic Silver, or a few others).

3a. With that said, I have not witnessed overheating CPU being a common issue with T4x Thinkpads. But, in any case, you can (and probably should) install TPFanControl to monitor your temperatures, and if you wish, modify fan behavior.