I have an Inspiron 8600 with a Pentium M @ 1.8GHz. I have A14 (the most recent) BIOS installed. I'm also running both Windows XP and Linux on it.
My problem is when the system heats up, the fan kicks on and the CPU drops to 600MHz usually rendering the computer useless. Even when the temp lowers to 36C it still keeps the fan on and the CPU slows. Prior to that though the CPU throttles properly, but the fan doesn't seem to be utilizing all speeds... either fast or off. At first I thought this was an OS issue so I compared both Win XP and Linux. Linux seems to run cooler (takes ~10 minute to heat up vs XP's ~4) but the result is the same. Both OS's experience CPU drops to 600MHz and high fan speeds. Neither OS ever sees a return to the full (or any other) speed of the CPU. Then I noticed while adjusting the BIOs, the CPU was listed as Current Speed 1.8GHz but suddenly the fan kicked on and it dropped to 600MHz. This leads me to believe there is something else going on here. I checked the cooling fan and heatsink and they a free and clear. I flashed down to A10, then up to A11, A12, A13 and now I'm back to A14. All have the same results.
Has anyone else experienced this issue and what can I do about it? I'd hate to toss the Laptop since everything else is running fine, until it heats up anyway.