Cpu fan abnormally works, please help me.

[Pechy2277]

Hi, I have trouble with cpu fan, and if i search where i want i cant find solution. I upgraded to new case, and upgraded graphics card.

My motherboard and cpu with cooler is from some original Dell. Some vostro as i know.

My cpu fan spin normally and randomly kick up at full speed with no reason. Then it runs sometimes like half minute in high speed and then it spin normally. And after some time it starts spin fast, i look to some info and it said that cpu fan have 4500 rpm. Duration how long it spin normal and how long it spin very fast is randomly changing. And cpu have normally like 35°.

I think that cpu fan kick at that very high speed, if the procesor reach 40°, i was looking to some app which show me cpu temp. But Im not sure about that and its just note. It maybe can help us with solving this problem.

It always on startup says system fan failure, but im sure its because in original case is one fan pre installed and connected on motherboard to sys fan connector. Now in new case i have connected fans to potentiometer so i can regulate it how i want. And on motherboard is all 2 connectors to fan non-connected. But i type it there,because it can have some reason on my trouble with that cpu fan.

From original dell computer i have only motherboard and cpu with cooler. And maybe hdd is original too.

I want to set that cpu fan somewhere in bios but dont find that and i dont change in bios nothing , and before in that original case it worked fine.

Im sorry for my bad english, but I think you understand what i mean.

Thanks for any help and I believe it will soon be resolved.

[veeg]

Hello

Correct me if i am wrong here,you said that the sys fans are not connected to your new setup?

[Pechy2277]

Hello

Correct me if i am wrong here,you said that the sys fans are not connected to your new setup?

Yes. But cpu fan is connected. I dont want to connect my fans to motherboard because i think it cant be regulated how i want on this motherboard. So i have connected them to psu and regulator.

Edit: to motherboard is connected cpu fan, other 4 fans installed on my case i have connected to psu

[phillpower2]

Is the CPU cooling fan connected directly to the CPU fan header on the motherboard.

Dell BIOS is one of the most basic that you will find and it does not like being tampered with.

[Pechy2277]

Is the CPU cooling fan connected directly to the CPU fan header on the motherboard.

Dell BIOS is one of the most basic that you will find and it does not like being tampered with.

How do you mean that fan connection? Its correctly connected to cpu fan connector. I triyed all.. i tried to connect optical drive from old case, i tried to start it without that new graphics card, because original pc worked on integrated graphics and worked fine, nothing helped. And cpu fan still randomly kicks up at 4500 rpm. So i think its mistake somewhere in bios or i dont know, before upgrade it worked fine. I disconnected graphics card and connected optical drive, so it was like in old case before upgrade. And it not helped.

[Rustys]

You stated that you moved the motherboard and CPU did you remove the CPU at all form the motherboard?
Did you clean off the old and replace new thermal goop.

Where do you have the power coming from for the CPU Fan?
Some mother boards require the CPU fan to be connected to the motherboard to work properly. Fans are designed to spin at certain rates so make sure that fan is not spinning above it rate before you ruin it.

What is the make and model of the graphics card?
Some graphics cars require 300 watts to power them.

Are you using the same Power Supply that was in the original Dell?
Dell is notorious for using just big enough power supplies to power just what is installed usually a 250 watts. Unless that power supply is powerful enough it may not have enough wattage to power the video card and all of the other stuff attached.

[phillpower2]

How do you mean that fan connection? Its correctly connected to cpu fan connector.

If the CPU cooling fan is the three pin type and it is connected to the correct CPU fan header on the MB there is nothing that you can do to control the CPU cooling fan speed and the fan is doing what it is being told to do by the thermal diode on the MB, the fact that the CPU temps only vary between 35° and 40° C suggests that the CPU cooling fan, heatsink and thermal compound are all in good order.

To be able to control the CPU cooling fan speed you would need the four pin type CPU cooling fan and the ability to be able to change any settings in the Dell BIOS, as said Dell BIOS is very limited when it comes to being able to make adjustments such as fan speeds + the older the MB the lower the spec and the more limited any end user adjustments are.

[Pechy2277]

Guys thank you much for reply and help, but i fixed it. I just updated bios from their original site and it works fine. Thank for reply, have a good day.

[phillpower2]

Great news and thanks for letting us know Pechy2277 (y)