So I suggest that we should include the following information when talking about this problem.
1. Hardware configuration
2687D5U, 2G Hz, 2G RAM, V3200, Fuji 5400RPM 80G
2. Software configuration
Windows XP SP2, BIOS: 1.23, Embedded Controller: 1.03
3. Power scheme ( Powersource: CPU, FAN, Brightness )
AC: Adaptive, Balance all, 4
DC: Lowest, Balance, 0
4. Using mobmeter, I observed:
Just after resume ( I seldom shutdown, only suspend) for a long time, CPU is below 40C, so the fan is off.
After a while, when the CPU reaches 46, the fan will be on, but at the first level, so barely hearable.
When the CPU arrives 48/49C, the fan reaches second level, and is quite noisy in a quiet room.
5. INTERESTING OBSERVATIONS
1. By accident, I found out that when my CPU is at 49C and fan is at second level, if I switch to "Maximum Performance" scheme which is built in, the fan will down to level 1 for about 5 minutes, while the CPU temp is still at 49!
2. If I use Powerplay to set the video card to be battery optimized while using AC, it can help to reduce the CPU temp down 1-2C, and delaying the triggering of level 2 fan a little bit.
3. It seems that the harddisk temperature might be another source for triggering the fan, though I haven't found any relation, I hope others might be able to report. It seems that the Fuji 5400RPM 80G is pretty hot, mine is around 48C under normal operation, while I saw that the latest 7200RPM is at 40-42 under normal load!
4. Setting the CPU in the power scheme to be "maximum" will not make it stick with the highest freq of your CPU! Strange, but true on my computer.
6. INITIAL CONCLUSION
The fan is all controlled by this "IBM Power Manager" stuff with regard to whatever temperature they get, if we can trace and debug this dude, we might be able to do something. I wish I knew about related knowledge such as ACPI, windows driver debugging etc. So what I can do now is switching power scheme while it gets noisy, this stupid workaround seems to be working!
All in all, this is definitely a FIRMWARE/SOFTWARE bug, they just don't want to fix it since it is not on the critical list.
Added at 11:07AM, Nov 9: This leads me thinking the difference between my power scheme and the "Maximum Performance" scheme, it should be "Fan control option", by setting it to be "Maximize Performance", you are telling it to tolerate higher system temperature. This actually has been reported by somebody before. So I modified my power scheme to be:
AC: Adaptive, Max, 4
DC: Lowest, Max, 0
And now, the fan will remain at level 1 while the CPU temp is at 48! Under normal system load, such as text editing and web browsing, my temperature will not exceed 48C, which means the fan will stay at level 1!
Still, it would be nice to know how to modify this power driver and change its threshold.
Added at 12:33PM, Nov 9: I tested the battery option, and interestingly, for battery scheme, you should set the fan control to be "balance all", and this will tolerate higher temp than setting to "maximize performace". So now my scheme is:
AC: Adaptive, Max, 4
DC: Lowest, Balance all, 0
Added at 6:07PM, Nov 9: Interestingly, with my latest setting, and if I put my laptop on my Port Replicator II, 48C will still trigger the fan to level 2, but it will not without the PRII. It seems that the fan control program is really COMPLICATED!
Added at 6:07PM, Nov 9:Obviously, there is an ambient temp sensor and the Power Manager will take that into account. With my current power scheme, if I am in the lab, which is pretty cool (20C), the fan will not go to level 2 at 49C. But if I am at home, which is pretty warm (25C), the fan will go to level 2 at 49C.
Added at 6:07PM, Nov 13: It is almost for sure that the Power Manager will reset something when you change/re-select a power scheme. My computer now always acts this way: (AC: Adaptive, Max, 4)
- When CPU reaches 46C, the fan will turn on at level 1, which is not even as loud as the harddisk.
- When CPU reaches 49C(Warm room temp)/51C(Cool room temp), the fan will upgrade to level 2, which is quite noisy in a very quiet room.
- When CPU get down to 48C, the fan is still on level 2, but if I reselect the profile, it will go to level 1 immediately!
THOUGHTS
After searching this forum and other BBS, here are some thoughts:
1. Changing the Power Scheme helps only a little bit unless we hack the Power Manager.
2. Using CHC(NHC)/RMClock can reduce the CPU and GPU temperature and hopefully will not trigger the fan to be at level 2 (We all agree that level 1 is just humming and acceptable). But I am quite a conservative person and I don't want to do this undervolting thing.
3. Using Arctic Silver 5 might help reduce 2-4 degrees of the CPU. I am planning on buying some and see if it really helps.
4. Hacking the Power Manager and/or even the BIOS/Embedded Controller. I guess starting from the Power Manager makes more sense since I think most of the "control decision" is made by this dude.
The shortcut to this Power Manager is: C:\WINDOWS\system32\rundll32.exe C:\PROGRA~1\ThinkPad\UTILIT~1\PWRMGR.OCX,StartPowerManager, so diassemble this .OCX file should be a good start.
I found this Neuron PE Disassembler v.1.0 b3 (it is a shareware), and might work.
All sorts of feedbacks and comments are welcome!





