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Strange CPU temp behaviour

Last response: in CPUs
November 23, 2013 12:12:58 PM

Hi guys

First time posting on the forums and I hope you can help.

I bought 4 additional 120mm case fans for my new rig. 2 to go on the cases side (intakes) 1 one the front (intake) 1 at the top of the case (exhaust). The p.c came with 1 front intake and 1 rear exhaust already installed.

The problem is ever since installing the new fans my cpu fan wont spin up faster than 3,500rpm causing it reach temps of 78°.

I know it’s the new fans causing the problem because while the p.c is under load and reached 78° I have turned the new fans off and the cpu fan then climes to nearly 6,000 rpm and brings the temp down to 65°. If I then plug the new fans back in again the cpu fan rpms drop back to 3,500 rpm and temp climes again.

My only idea is that one of the new fans is blowing on a temp sensor or something causing the cpu fan to think its spinning faster than it actually is?

Any ideas guys, this is driving my crazy!

Stock AMD heatsink and fan
AMD 8350
8 gig Ram
650w PSU
Windows 8 64bit
Nvidia 660 TI
XPredator X1 case
a c 375 à CPUs
November 23, 2013 12:42:24 PM


What's your motherboard?
And the brand/model of that PSU?
a c 92 à CPUs
November 23, 2013 12:48:45 PM

78'c is too hot..
Even 65'c is too hot for your processor..

The max daily temp for this cpu is 60'c.

Reseat your maybe not perfectly contact between heatsink and processor..

And i suggest you to buy after market cooling..

Cooler master 212+ is a good cooler for budget user..
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a b à CPUs
November 23, 2013 12:54:10 PM

Ok first of all .. 6000 rpm ?! 6000 rounds per minutes?! Thats 100 rounds per second, but I guess it is the AMD stock cooler.
Well from what I saw I do not think that the side fans should be for intake . What I suggest, 1 or 2 on the side for exhaust no intake . You probably know about this but take a look:

What I believe is happening is that the side ones pulling the air inside while the CPU cooler pushes the air outside so the air current is kinda '' colliding'' between and some hot air might remain inside the case

If you still have no progress then an aftermarket cooler might be a solution .
November 23, 2013 1:18:16 PM

Hi guys

Thanks for the replys

My mobo is a: gigabyte 990xa-ud3
PSU: Cooler master 650w GX Bronze

Think i may take your advice and invest in a new cooler. The Corsair H80i cooler seems to be pretty solid.

Best solution

a b à CPUs
November 23, 2013 1:19:17 PM

I though also of a theory than might be causing the lower rpms on the CPU fan.
Well your CPU fan pulls hot air from the CPU . So, as the hot air being lighter than the cool air ( physics ) it is getting higher and it is being exhausted by the top and the rear fan. Also the side fans are trying to push inside your case cool air from the outside( you said you have them for intaking ) . So if one of them is exactly across the CPU fan the air that is coming in is trying to roll the CPU fan from the other direction than it is already spinning ( most of the hot air is higher as I told so it wont block that much the cold air ).

This was happening to the system of one of my friends and I hadn't seen it before although it did not make sense . I would say side fans are almost all of the times for intake , but since I saw that...

November 23, 2013 1:42:05 PM


Thanks for your ideas. I think you may be right.

Im going to have a 'play' with the fan set up in my case tomorrow and report back just encase any one else has this issue in future.

Thanks again :) 
a b à CPUs
November 23, 2013 1:48:41 PM

chillyballs said:

Thanks for your ideas. I think you may be right.

Im going to have a 'play' with the fan set up in my case tomorrow and report back just encase any one else has this issue in future.

Thanks again :) 

It is just a theory, I hope it will work. Good luck