Vibrating Ultra 120 Extreme Cooler

[eirche]

i just built a computer. it has Ultra 120 Extreme cooler with Noctua NF-P12 fan. the cooler vibrates about 5-20Hz. the vibration is visually noticeable. i can feel it with my finger. it stops if i hold the cooler. it doesn't make any audible noise.

i concern that prolong vibration will cause physical damage to the computer, and that heat paste will flow away. i use arctic silver 5.

what do you think? do i need to do something about the vibration?

 

[Evilonigiri]

Interesting problem. That is an excellent cpu fan, so I don't know why it vibrates. Does the TRUE vibrate without the fan?

 

[eirche]

no vibration when fan is off or without the fan. this low frequency vibration is probably resonance, which can be cause by fan vibration or air turbulence.

and i have those anti-vibration sticker on.

 

[bildo123]

I thought this thread was going to have a discussion of.....other sorts....

 

[SpinachEater]

I thought this thread was going to have a discussion of.....other sorts....

Hehe, that is what drew me to it. I was thinking of some witty comments before I even saw the problem.

No but seriously...it sounds like the uneven load in the washing machine problem. Maybe something is out of balance in one of the fan blades. Have you tried a different fan? Does the fan vibrate when it is not on the sink like...if you hold just the fan and let it run?

Also...teach me how you can estimate Hz with your eye / finger...

 

[eirche]

Also...teach me how you can estimate Hz with your eye / finger...

it's faster than i can track and count each beat, 5Hz. it's slower than fan vibration by fan itself, 1300rpm = 22Hz. so my guess is 5-20Hz.

two Noctua fans gave same result. the fan by itself gives off some vibration at higher frequency and less violent.

at the moment i use a rubber air duct to mitigate the vibration to acceptable level.

i think that both IHS and cooler have convex surfaces (bulged center). contact surface is small. much like two balls touch each other and they can roll. i think i can solve the problem by lapping IHS and the cooler.

 

[Mugz]

Try that, also try vibration dampers on the fan mounts.

Check the fans themselves, compare to other brands, find ones that are nicely balanced.

If you're really into going into detail, get small weights and balance the fans.

 

[SpinachEater]

Ah, so your HS is sort of rocking back and forth on the CPU surface? This page has a good pick of the convex surface. Is yours like that?

http://www.frostytech.com/articleview.cfm?articleid=2244&page=2

 

[eirche]

no, it looked quite flat when i have it again a straight edge.

 

[Evilonigiri]

I'd say return the fan for a new one. It's quite expensive, $20 right?

 

[eirche]

$18CND each, about the same in US dollar. i ordered them online. it can be a hassle to return or exchange. i am going to use them not as a CPU fan. i will try other brand of fan. the air duct dampens the vibration somewhat. so it's kind of ok for now.