Hi everyone,

I'm new to these forums, and just found them when searching for a solution to my current problem. I have a Dell XPS 400, and recently installed a second internal SATA HDD (Western Digital 500GB 7200 RPM 16MB Cache). I noticed that the floor where the tower sits now constantly vibrates with a low, yet audible, whirring, as if something were spinning off-kilter. I suspected a problem with the new hard drive, so ran the system with the side cover open, with my hand on the HDD. The new HDD did not seem to be vibrating more than normal, especially not to extend that would make the floor vibrate.

As this is a second hard drive, only stores music and video files, and is not constantly accessed, I then thought that it would not be possible for the new HDD to be causing this constant, whirring vibration. However, when I take the second HDD out and just leave the first one installed, the vibration stops. Is it possible that the system makes the fan(s) work extra hard with the second hard drive installed, and this is causing the vibration? Or so you think this is a problem with the hard drive?

Thanks!

Some cases are pretty flimsy. When the side cover is off and you install something like a drive if the case is slightly twisted when tightening down screws you can get that result. If this might be the issue try setting the case on a flat hard surface and loosening the mounting screws to allow the case to flex back. then re-tighten.

Also possible you have a damaged or defective drive.

Hard drives are very well balanced and you shouldn't notice significant vibration from them, and they require very little power, so they don't add a significant load to your system, especially if used only for storage.

The sound you hear and the vibration may be your optical drive(s) spinning. Lots of optical drives are poorly balanced. Windows spins the optical drives at seemingly random times when they have a disk in them, often without lighting up the drive's led.
Remove any CDs or DVDs you have in drives, and try your computer for a while to see if the sound has gone away.

As OtheHill has said, some cases are flimsy, and because of that they are more prone to react audibly to vibration. To minimize optical drive or hard drive or fan vibration sounds, use 4 screws, 2 each side, to mount the drives.

If possible hold the drive in your hand while it's running. (You won't get zapped by it but don't let its circuit board touch any metal.) That might give you a better sense of whether it's off-balance.

If it seems to be OK try mounting the drive in a different orientation. That is, if it's mounted horizontally try to mount it vertically. If it's vertically mounted now, try it horizontally.

Thanks very much for your replies - this has always been a great resources of mine, even if I've just been a lurcher until now.

There are no discs in the optical drive, so that eliminates that problem. The vibration does sound like a CD spinning off-kilter a little bit though.

Both my internatl drives are held in plastic mounts that came with the XPS 400, which clip into pre-installed metal bays that the PC was built with. It has been described as a "tool-less BTX case". I wish there were some screws for me to tighten, but it's all "click in, click out".

I'm not sure if the plastic hard drive mount can be replaced with a rubbery one, or maybe even moved, but I think it's welded in place.

I'm fine with the added noise and vibration, as long as the hard drive isn't damaged, or doesn't become damaged. The drive is about a week old, and works perfectly, with not even the sound seeking noises. Could this sort of vibration just be normal for a tower with two HDD's mounted on the bottom?

The idea would be to somehow cancel out the energy being transferred to the case due to the angular momentum of the spinning disks inside the hard drives.

If you were able to mount one of the drives upside down that might do it. If they both spin in the same direction when right-side-up then turning one of them upside down would result in its disks spinning in the opposite direction. The result would hopefully be the affect of one drive would cancel out the other's.

That might be too simplistic an approach to the physics involved but it wouldn't hurt to try.

Otherwise, assuming the drive is good, the only other thing would be to muffle it by maybe setting the PC on top of a couple of mouse pads.

The vibration will not hurt the hard drive.

If it's not caused by an optical drive, it's a lot more likely the vibration is caused by a fan rather than a hard drive.

Some great ideas, guys...thank you! I will look into digging out some of my old mouse pads and placing the PC on those, and also if the "tool-less" hard drive mounts that came in my XPS 400 can be put in upside down.

I don't think the mounts can be inverted but you may be able to mount the drive upside down in the mount. I wouldn't recommend that myself. I think the bearings are designed for the orentation it is in now. What might be wrong is that one of the rails may not be lcking in place due to not being installed to the drive properly. The slides themselves could also be twisted. I know you didn't have a choice on that case but I won't buy a tooless case myself. Placing the case on a cushioned surface may help. That waffle type shelf liner may work better than mouse pads.Your floor may not be level either.

It doesn't matter to the drive's bearings which way the drive is oriented once it is spinning - the centrifugal force of the disks (platters) in the drive and the rotor of the motor makes that not relevant. It only matters for the tiny amount of time the drive is spinning up or spinning down, in which case the bearings wear slower if the drive is horizontal, right side up or upside down. I've had drives either way and it has made no difference.

The XPS 400 uses the case fan to divert heat from the cpu heat sink. If the shroud was dislodged while removing the side panel it could cause vibration. Also, if your machine is in a heavy dust enviroment, knocking the dust off of one of the blades could cause an imbalance in the fan.

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