Model: Samsung R590 CPU: Intel i5-450M 2.4Ghz -> 2.66Ghz OS: Windows 7 Home Premium 64 with SP1 (after restoring tested also without any updates)
It has 4 years now. After 2,5 - 3 years it started to turn off when I was playing games. It was then cleaned from dust and thermal grease was changed. This helped only a bit. The problem returned after a few weeks. Then i managed to change the maximum processor state to 90% in the power options and it prevented turning off for a few months, but caused an fps loss. Then it started to turn off again even with this setting. I had to clean it from dust (there wasn't too much of it) several times in this period of time to get it back to work. In the last week the problem occured again. I had enough and decided to do everything I could, which included:
- Restoring system to factory settings with Samsung Recovery Solution software included with the laptop which kept the factory system image with default drivers and Samsung programs.
- Cleaning from dust and changing thermal grease by myself.
- Checking the heatpipe with lighter if it transfers the heat to the other side (when disassembled of course).
It didn't help. If the setting in power options is not lower than 100%, laptop turns off after a minute of testing the processor with OCCT (if I disable temperature cap in this program. With the cap of 85*C the test stops in less than 10 seconds).
In the passive state the temperature of the processor is 35-40*C. With 99% maximum processor state setting, when testing with OCCT, temperature is not higher than 86*C and as I read on the internet it's probably the normal temperature for laptop's processors. When maximum processor state is set to 100% (default setting) during the test, turbo boost overclocks the processor to 2.66Ghz, temperature gradually increases up to 105*C (which seems to be a safety cap) in around 1 minute and then the laptop turns off.
GPU temperatures during tests of GPU are fine, so it's only CPU problem.
Question: What may be the reason of that and can I do anything to fix this? System is restored to factory settings along with standard drivers, it's clean inside with fresh thermal grease, heatpipe transports heat, fan is working, BIOS is original so the conditions are similar to initial, so why it overheats?
Additional research: (added 4.12.2014)
I did a little research with Speedfan, temps and fan speed (by ear). When 99% and testing, fan speed is fast and uniform. But when 100% the speed is fast first, then it eases down a bit and then accelerates again and so on. I think if it could keep the speed it wouldn't overheat. link this is a record of temps when testing with 100% (I stopped it after ~35 secs to prevent the turn off). There is something weird. At some point temperatures from "core" switch with that from "temp". The fan eases down in the same moment. It probably thinks that the temperature is lower so it don't have to work on full speed but it's wrong. Temp1 and Temp2 are sensors from ACPI chip. That behaviour doesn't exist when CPU is on 99%.