TR Forums

My system is quiet during normal operation but when I am playing a game the fans kick on. This is working as intended. The problem is that when the fans kick in I start getting waves of sound and vibration. Vroom, Vroom, Vroom, it's driving me a little crazy. It sounds like I am calling a sandworm.

So my questions are:
1) At what temperature should the fans kick in? (i7 2600k they currently kick in at 50 Celsius which I think is pretty low.
2) What can I do physically with the case and fans to help minimize the thrumming sound and vibration.

Thank you,
--Shoki

System specs:
CPU Intel Core i7-2600K
Motherboard ASRock Z68 Extreme7 Gen3
Video Card EVGA GeForce GTX 680 2GB
Memory Corsair Vengenance 16GB (4 x 4GB) DDR3 1600 (PC3 10600)
HDD Corsair Performance Pro 256GB SSD
HDD WD Caviar Green 2TB Drive for Steam
PSU Corsair AX850
Case Corsair Obsidian Series 650D
Cooling Thermaltake Water 2.0 Extreme
Monitor Panasonic VIERA 32-Inch 1080p 3D LED HDTV
Operating System Windows 8 Pro 64-bit

You'll want to put on rubber dampers between the case and fans.

Various things can be done, but I would first try to determine which fan (or set of fans) is causing the noise.

The low frequency pulsing is caused by two fans running at just ever so slightly different speeds, causing a beat frequency to be set up by the pressure wave of one fan striking the other just slightly out of phase.

What Ned Sed.

The culprits are usually graphics cards with twin fans or a pair of identical case fans running off a header than shares the same fan-control profile. Since you can't easily tweak the speed of one of these two fans you're better off trying to kill the rattle rather than stop the cause of the vibrarion.

9/10 times it's a side panel or front panel that's rattling. Prod various parts of your case with your finger until the buzzing stops, and then work on improving how well affixed to the rest of your case it is. I'm keen on that thin adhesive foam you can stick into door frames to stop draughts and reduce the noise of slamming doors.

Chrispy_ wrote:

9/10 times it's a side panel or front panel that's rattling. Prod various parts of your case with your finger until the buzzing stops, and then work on improving how well affixed to the rest of your case it is. I'm keen on that thin adhesive foam you can stick into door frames to stop draughts and reduce the noise of slamming doors.

Yup. even If the resonance is inherent in the case design, at least you can stop sh*t from rattling when the resonance kicks in. Even a folded up Post-It note, strategically wedged into a crevice somewhere, can do wonders!

just brew it! wrote:

Yup. even If the resonance is inherent in the case design, at least you can stop sh*t from rattling when the resonance kicks in. Even a folded up Post-It note, strategically wedged into a crevice somewhere, can do wonders!

An old Mazda 323GT I drove from 1988 to about 1996 had a nickel shoved into a gap in the dashboard panels to achieve the exact same effect.

Thanks everyone for the replies. The radiator has dual fans so it's probably that. I'll see what I can do to tighten things up around the case and maybe do some rubber mounting.

Sounds like everyone has explained this phenomenon pretty well. If you're a good singer, you can reproduce the effect easily. My favorite is to hum to a microwave. Get the same pitch, then slowly move your pitch up or down. The "wave" speed will start slow, as you move further from the microwave humming frequency the wave will speed up, then disappear. Same concept of how you tune a guitar.

The fix:
1) Locate the competing fans by placing a finger gently on the center hub of each fan to stop it briefly. Since fan noise is pretty quiet, it's most likely two fans that are close/next to each other that are exactly the same brand/model.
2) If you can't change the RPMs of either of the competing fans (via mobo or in-line resistor), simply swapping out one of them for a different fan will fix the problem.