I just bought a fractal define r3 case and moved my hardware to this case (NVIDIA GTX 470 paired with a intel core2duo e8500 cooled by thermalright silver arrow with only one of the two fans installed, and a corsair ax850 psu). so far i am happy with the noise level when browsing (the cpu cooler is spinning at 650rpm, the gpu fan at ~800 rpm and the psu is virtually silent, the case fans are also running at low speed ~600-700rpm). but as soon as i turn on a game and the gtx470 cooler starts to work the case starts to vibrate and resonate and produces more noise than necessary. how can i improve the acoustics/noise dampening of this case?

i already moved the front intake fan to the bottom inlet (next to the psu) to get more fresh air directly to the gtx470. this helped a bit - but is not enough.

i was thinking about putting some bitumen mats on the side panels to make them heavier and less prone to vibrations. one problem is, the silver arrow is so high that there is almost no space left for a thick insulation. in addition i am realizing that the pre installed foam on the side panels might render any bitumen mat glued on top of the foam useless. does anybody have any experience with adding extra sound-proofing layers to the side pannels?

another idea of mine is to seal the front intake (the slits on the side) to reduce the leaking of noise. only the bottom intake fan would than provide the fresh air. any ideas on this?

Are the side panels vibrating? If so try to just add some resistance to them so they're not loose. See if that solves the problem.

No problem with vibration from any HDD? Just the GPU fan speed affecting it? Try to manually put the fan on Max and then dial it down (not running any games and stuff) and see at what % the vibration becomes a problem.

The side (and top) panels are not loose - they are vibrating like the skin of a drum. I am using a SSD, the HDD is off most of the time and when on it doen't make any perceptible noise. The only real source of noise is the GPU fan. It doesn't really matter at which percentage the GPU fan is too noise for the (factory) noise-dampening of the define r3. Maybe all the details in the OP distract from my question: what can be done to improve the noise-dampening of the define r3 without wasting money and time?

This doesn't seem like a case issue, really. If it is causing the case panels to vibrate, that suggests you have a noise VGA cooler, perhaps the fan is imbalanced or has damaged bearing. There are no cases -- marketed as "silent" or not -- that will make a noisy fan inaudible. I would not wast any time trying to further "soundproof" the case, as that will only lead to frustrations. Seek, instead, to reduce the noise of your video card cooler. Replacing the existing cooler with a good aftermarket cooler is probably the route to go. We've reviewed a bunch.

Have you opened it up to listen to the gpu itself? Maybe that's vibrating. Take a look and identify the problems, use some OC software to crank the fan up as required. If the gpu fans don't make the vibration then something else is making the noise. You just have to identify it.

it really is a resonance problem. i tuned the gpu fan profile and added a 140mm fan to the bottom vent. now i have a 120mm front intake fan, a 140mm bottom intake fan, and a 120mm exhaust fan at the back. all fans are spinning fairly slow and make almost no noise. with the configuration the gpu fan can spin at lower RPMs which makes the whole system quieter over all. btw. i have this gpu. anyways, is there really nobody that added soundproofing to this case?

There's no soundproofing to be done with a graphics card fan that vibrates so badly, it should be replaced. Try finding out if one of those three card fans is especially problematic during load.