Hi everyone

For a while I've had a problem with my PC making a strange pulsing sound, around every second or so, and it's hard to describe. It sounds like the fan gets louder during each pulse, as if a person was turning the volume up and down. The thing is I can feel the pulsing through the PC desk, and on the PC itself. However, when I remove the side section of the PC case, the pulsing sound goes and there is just a constant fan noise. I don't really want to leave the case off because it will get dust in it, and it doesn't look like anything is pushing against it or anything. Any ideas?

Hi ianpwilliams,
Are all the vent holes in the case clear of dust?
I'll also mark this as Open to encourage others to add their input
Thanks for your patience.

Mmmm very peculiar.

Make sure the psu screws are not loose, likewise check all case fan screws, check the cpu heatsink fan is secure also.

How many fans have you inside your case?
What direction is the airflow from the fans?

It can be that one is placed so that the airflow "pushes" against the airflow from another, hence the rythmic sound.

All the fans seem fine to me, all properly screwed in and in the right place. I've noticed that when I take the side panel off the pulsing is actually still there, only it's a lot less prominent.

Well the only things that can be making whatever sound that you hear are the fans or the hard drive.

You don't have any obscure neon lights parked up in it do you?

Can't see anything wrong. And it's hard to tell where the sound is coming from, without putting a microphone in there to see where it's coming from. I installed a second hard drive months ago, which eventually died on me. Then I installed a second one more recently, which is fine so far. The only thing that I can think might be causing it is these new hard drives.