CPU Fan RPM not being managed correctly - causing very hot temperatures

Thomas5020

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Hi. I've got an i7 4790 and for some reason, the fan isn't doing its job properly. It's either very low or very high RPM. The power plan cooling option is also on active, not passive. I have also checked the BIOS for a setting and found nothing. It sits at inaudible speeds until the CPU gets to around 98c then it gets extremely fast until it cools to around 95c under load. When idling with around 10-20% usage the temperature is at 70c+. Microsoft couldn't help me with this issue. Minecraft is also performing very badly at around 30fps, but other games run fine. The only case fan at the back may also be speeding up but I don't have much of a way to tell. What could be the cause?

EDIT: Just seen the fan go from 2300rpm in speedfan (just installed it) to over 4500rpm for a second then straight back down to 2300rpm again, with the cpu temp going from 95c, to 95c (lol). Just seems to be doing it randomly
 
Solution
Ok...if that is the case, what I would do next (I HATE these OEM boards, by the way :) ) is 1) either take the cpu fan and unplug it from the motherboard. And hopefully there will be another chassis fan connection on the motherboard that you can stretch the cpu fan cable to and plug it in there. These chassis fan connections often simply supply the full 12 volts if they are 2 pin connections.. if they are a 3 pin or 4 pin connection, they will be controlled by pwm type of controllers so no go. 2) if there are no nearby 2 pin chassis fan connectors, you'll need to buy or obtain another fan the same size as the one on your cpu fansink, of the 2 pin variety (red and black 2 pin cable). These usually come with a romex type adaptor so that...

way2aware

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What kind of motherboard do you have? If it is a non oem type (i.e. Asus, Gigabyte, Asrock, Evga,etc) it will have an option in the 'monitoring' section of your bios to either let the cooling be based on temperature requirements, or disabled (meaning the fan runs at 100%). Try this first and see what it changes for you
Anything in the 90 degree range is unacceptable, man
 

Thomas5020

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It's an MSI motherboard but it is one that is custom made by them specifically for my model of PC (HP Envy 700 311na) so I don't think it will have the option. But when I am next at my computer is will have a look.
 

Thomas5020

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Just looked, there is no option for monitoring

 

way2aware

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Ok...if that is the case, what I would do next (I HATE these OEM boards, by the way :) ) is 1) either take the cpu fan and unplug it from the motherboard. And hopefully there will be another chassis fan connection on the motherboard that you can stretch the cpu fan cable to and plug it in there. These chassis fan connections often simply supply the full 12 volts if they are 2 pin connections.. if they are a 3 pin or 4 pin connection, they will be controlled by pwm type of controllers so no go. 2) if there are no nearby 2 pin chassis fan connectors, you'll need to buy or obtain another fan the same size as the one on your cpu fansink, of the 2 pin variety (red and black 2 pin cable). These usually come with a romex type adaptor so that you can plug it into one of the unused romex connectors on your power supply harness. I have in the past just wired them directly by cutting any unused yellow, and black wire on your power supply harness, and cut the connector off of the fan cable. You wire the yellow (from power supply +12 volts to the red wire of the fan, and black to black, using wirenuts. Now you have 12 volts going to that fan at all times. You will need to take the fan that you removed and install it somewhere, leaving it plugged into the CPU fan connector as your bios may not let the computer pass post without a fan plugged into it. 3) you can buy a new CPU fan that is the same size as the one on your CPU and that comes with the same 3 or 4 wire cable on it and try that fan, just to see if its the fan that is at fault. Another option is to buy another CPU heatsink and fan assembly altogether... for your CPU I would suggest a Corsair H60 or H80, or a cooler master hyper 212, maybe. And thermal paste of course- always arctic silver 5.
I listed the above possible solutions in ascending order as regards the cost- it's almost a certainty that one of those will solve your problem on the cooling. Sorry it seems kinda convoluted, but that's the breaks when you're dealing with locked bios OEM motherboards.
 
Solution

way2aware

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One more thing... try switching the power plan cooling option from active, to passive. This might also just supply the full 12 volts to the fan at all times. Do this first, and watch those temps and shut it off if they start climbing to the moon right away.
 

Thomas5020

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Thanks for the help! I will get to work tonight. A new cooler like the H60 isn't possible in my case though I should say. The case has only 1 space for a fan and it is on the back used to pull hot air away from the cpu and out of the back. As for the Hyper 212, I had been considering that for a while, as i have been considering getting a new case and motherboard as my current one is inverted :/

 

Thomas5020

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There's one free fan connector labelled as PUMP_FAN1. CPU fan is currently in one called CPU_FAN1 and the case fan SYS_FAN1. That free connector should do the job, right?



 

way2aware

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Yes, that one should work. However, you are most likely going to need to plug a fan into the cpu fan connector to satisfy your system that there is actually a fan cooling your cpu installed. You'll need another 3 pin fan, or 4 pin.