Fractal Design R3 side fan whiny/noisy?

[Ika]

I received my Scythe Slipstream 1200RPM fans yesterday in the mail, and proceeded to spend my night putting together my rig and doing all the cable management. My current cooling scheme is: two front intakes, one rear exhaust, PSU exhaust (XFX Pro 750W XXX Edition), and either a side or front top intake, along with a Hyper 212+ and a Palit GTX460 Sonic 1gb GPU. All four of the Slip stream fans are hooked up to two of the fan controllers the Fractal comes with - supposedly 6v -> 12v adjustment, on a PCI bracket.

I decided to run a side intake for now, because the Palit's stock fan (80mm) gets screamingly loud when the GPU hits full load, and I want it to get all the cool air it can before I replace the cooler with a Scythe Setsugen 2, possibly with a 120x25mm fan.

However, at full 12V, besides the "whoosh" of air from the front and back fans and the whine of the CPU and GPU fans, I noticed a very distinct tonality I hadn't heard before coming from the case. Undervolting it reduces the tonality, but it's still present, and a little annoying. I took off the side panel and confirmed that the noise was coming from the side fan alone, and if I put my hand over the vents, the turbulence increased but the whine went away. Even when the fan is undervolted to 6v and attached to TWO 12v->9V adapters from Jab-Tech, the whine is present. Has anyone else experienced this with an R3 side intake fan? Would swapping to a 140mm fan make a difference? Maybe a different bearing type - BB or FDB?

 

[lehtv]

Alright here's my theory with regard to whining noise on the fan installed as an intake on the side slot. Normally the fan blades will spin very close to the mesh and cause air between the blades and the mesh to make much more noise than the air that simply passes through the fan. In my experience this is an issue even at very low RPM levels. Installing a separate fan filter should help, as then the noise output will be similar to the noise made by the already filtered front fans. I'm not 100% sure if this is true when using a 120mm fan in the 140mm slot; 120mm spin at higher RPM so it's possible that it'd still whine a bit. I've used a 140mm Thermaltake fan on the side slot, with and without a filter. It was whiny without a filter, but when filtered it was pretty quiet at 500RPM.

I doubt it's the fan bearing, you can easily test whether it makes whining noise by powering it on without attaching it to a slot.

Some other thoughts:

In my experience, having an exhaust fan in the rear-top slot of the R3 helps with GPU temperatures a degree or two as it reduces heat buildup (just one exhaust isn't enough). Since you have the PSU as an exhaust though, I don't know if that would matter. I prefer having the PSU take in cool air though, and let the hot air rise and be exhausted from the top.

I use a 140mm fan as a bottom intake*, along with the two front fans, just to make sure enough cool air is supplied. I have a 560 Ti too and I prefer not using a side fan at the moment, as the case is on my right side and blocking that slot helps reduce load noise a bit.

I don't recommend a top intake when you're using front intakes as well. I've tested it and it counteracts the airflow from below; CPU and GPU temperatures were the same, but HDD temperatures were a couple of degrees higher.

*in total my fan setup is as follows: 2x120mm Silverstone front intakes, stock Fractal 120mm rear and top-rear exhausts, 140mm Sharkoon floor intake.

 

[Patrick Wolf]

I've experienced this on the CM 690. I used the frame of a 120mm fan to put some distance between the vent and fan which eliminated the whine.

 

[Rhezuss]

I have the same whine on my 2 side panel 120mm fans (intakes) and no whine from the rear and top ones (exhaust).

What lehtv explained must be it, air coming in from the side mesh panel must cause this whine since.

I simply removed them, no more whine and no difference in my temps.

 

[Ika]

Yeah, after Googling all day I'm pretty sure turbulence is the problem. I'll probably remove it and put it on my Hyper 212, saving myself the expense and difficulty of looking for a Gentle Typhoon (why are they so hard to find? ;_.

If I move the fan away from the side panel via spacers or grommets, how much space do I need to reduce the turbulence to inaudibility? I may look for a 140mm fan, space it via spacers or grommets, find a way to mount it with longer screws or something, and see what happens. Or I'll just leave it open and deal with it, my temps seems to be decent.