Precision M4300 fan problem...

I have a Precision M4300.It has a strange problem from a long long time.

Sometimes the Fan doesn't start when the temperatures are high enough.I mean,normally the fan starts when the gpu reaches 65 C and works with 2500rpm until it cools down the CPU to 35-40C.
But SOMETIMES it doesn't start at 65 and when the temperature gets very high( 75-80C) it starts at 4500/5000rpm and DOESN'T STOP untill restart.It's very annoying,i use I8KfanGUI to slow the fan down...but i can't understand what couses it?

I tried with different BIOS(A7/A12/A13),different Windows,BIOS settings at default...but it still happens SOMETIMES

p.s:sorry for putting the thread here,not in precision section : Move it,if needed...

 

good to see your using I8K, have you tried cleaning your fans out with compressed air?

If you have the time and tech ability, I would suggest taking the laptop apart and cleaning the fans that way. you might even get lucky and only have to go so far as take the keyboard off. If you really have the time, disassemble and redo the heatsinks with arctic silver 5.

 

1.I have I8K but i prefer not to use it because it doesn't work nice with the precision's chipset

2.I have disassembled the laptop and and the fans can't be reached only with taking the keyboard out. Although i have cleaned them 1-2 times.

But i don't think dust is the problem,because when the fan is working properly the laptop is very cool and there are no problems...even when gaming the fan rarely works at more than 2500-3000rpm.

THE PROBLEM is that sometimes the fan DOESN'T start at normal temperatures(55-60C).It starts when it reaches 75-85C and works at 5000rpm ...even when it cools down. When it does like that i start I8k and the fan slows down...and when i shut I8K down the fan starts spinning at 5000rpm again...so i should restart it to stop the fan. It's very weird and i'm sure it's a bios/software problem.