low hum and fan on off like crazy

hi guys

firstly when i turn my laptop on it is fine, no fan noise no hum. after i play some games its also ok, works as it should.

but every now and then, such as towards the end of the day the hum sound of the laptop becomes loud enough to irratate the person next to my room. when the laptop is shut down their is an audible pop or release of some kind. its similar sound to if you leave speakers plugged in and they hum and then u unplug them.

secondly, the fan is fine for the most part, but last night i was to leave a download on and i noticed the fan was repeatedly turning itself on and off very frequently. i googled a quick fix which was to put the laptop into sleep and then back on again an then the fan was fine.

any solutions to these problems, the hum is a bit annoying and the fan on and off is worrying that it is wearing away its longetivity.

i dont have gpu/cpu heat reading gadgets or software installed as i know these can cause the fan to start on and off.

any help would be appreciated

 

Not sure about the fan, but the hum and pop when shutdown could very well be coming from the speakers. If this was stereo equipment, I would suspect a bad ground somewhere.

Is there any change in the hum when you turn down the volume or mute the speakers?

How about if you plug in some headphones.. that should cut out the speakers altogether.

 

what is normal fan behaviour?

for example, downloading in origin and running firefox, should the fan be going on and off every so often? temps are 54-57