Riou

When I put a high CFM but reasonably quiet fan (like a S-FLEX G) in a pull configuration on the Megahalems, there is this weird squealing, tonal noise. It is almost like the Megahalems is whistling when the air is sucked through the fins.

Lower CFM fans do not exhibit this problem. Even higher CFM fans...well you cannot hear yourself think anyways.

A push fan configuration does not suffer from this problem.

Does anyone else have a Megahalems with the same characteristics?

Maestrotogo

Wow that is weird. Why was it in pull config? No room by RAM? Also join the Megahalem club in my sig!!!

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akeedthe

i just use a panflo 120x38...but for fun that other day...i hooked up another fan aswell in push pull...no squeal...

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GoHigh

You know, I had this problem too when I had my S-Flex Gs in Push/Pull with my Megahalem. I unmounted the fans, and tested them, and they were fine. The was a bit odd, so I just changed out the fans with Kazes, and no more squeal.

I never retried the whole thing again, but I figured it was the way I had it mounted or something.

I just ended up using the S-Flex as my exhaust fans.

KILLER_K

You could try spacing them out a little bit and see if that helps. Could just be static pressure between the two causing the issue.

Cuar

I have the same issue and it seems it is from the air pushing through the megahalems. I took my push fan off and it doesn't make a squeal but when you hold the fan off of heatsink just a bit it wont do it. If you move it a little bit closer it will start up again. I'm guessing its from all the static Pressure of the fans I have two Sflex F's Similar to your G's so it must be the issue. maybe there is some way to put something in the corners to help prop it away from the heat sink a little bit. I don't know if it will hurt it or make temps rise. Something I will possible test when I get some time. Ill let ya know what I find out. BTW my temps dropped from 45C idle to 34C amazing what fans can do....

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Rab1t_K1ll3r^

This is an odd problem. By the sound of it the air is making the fins vibrate, Just a guess. If another user has had the same problem then you needn't worry.

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IRknnT

two nmb-mat 3000 rpms in push-pull on megahalems, get the same squealing noise like a pig...gonna try mounting antivibration bolts to all the fans then hooking them on to try increase the spacing as KILLER_K said

Cuar

Just need to deal with a annoying noise!

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Riou

Well I found a way to reduce the pitchy noise a bit on the S-FLEX. I had some extra silicone rubber grommets from an Antec case and put them into the holes of the S-FLEX. I put them on backwards so the cap of the grommets will be a cushion between the fan and the heatsink. It is a tight fit to put on the 25mm fan clips now though.

The pull fan makes much less noise now. There is still a little bit of noise if you try to notice it, but it is much better than before. It sounds a little softer than the noise from a Zalman 9500 fan. If you undervolt the S-FLEX to ~1200 rpm, it should be almost silent now.

These Megas really cool well. They just do not like high speed S-FLEX fans as much.