Three things you could investigate:1) Any Core i7 (possibly i5) with C-state support enabled -- specifically, C-state transitioning between C3/C6.
On every Core i7 system I have (one HP laptop (not sure which rev/stepping), and one desktop (i7-2600K, rev D2 / stepping 7)), I have to turn this feature off, simply because the transition between the two CPU sleep states is audible. Yeah, even within a Fractal Design R3 case I can still hear the CPU transitioning between the two. I solve the problem on my laptop using ThrottleStop (since the HP system BIOS offers no way to disable C3/C6), and I solve the problem on my desktop using the system BIOS. Lenovo laptops (which I also use at work) have the same problem, but offer the disable feature via the BIOS.
I should note this noise isn't audible to a lot of people, but is to some others. In fact, at work (where my laptop is) most of my colleagues can't hear the noise. There's only one other than me who can hear it -- and only after I pointed it out to him and asked him to listen closely (he's also a musician, heh). Now it drives him just as crazy as it does me.Here's a Youtube video
which exhibits the problem. Just search Google for "Core i7 c3 c6 high pitch" and you'll find lots of hits.
This is a pretty well-known problem, but it's also pretty low-level. Good luck on getting this one fixed; will require getting past a lot of red tape with Intel.2) The infamous "siren" coming from PSUs when using tools like ATITool "spinning cube".
Happens with ATI cards or nVidia cards.
Supposedly MSI was one of the companies who addressed this problem
, but I own a MSI N560GTX-TI Twin Frozr II and it has this issue. PSU is a Corsair Professional Series Gold AX850. Same happened using an Antec PSU.
So it seems to me that MSI at one time cared about this problem, fixed it (yay!), but then forgot it was occurring and now we're back at square one. What's amusing is that the GTX 200 series came out in roughly 2008/2009, and it's now 2012. So in only a few years they forgot.
They aren't the only one either. Google for something like "video card frequency noise" and be amazed.3) Logitech mice.
I have been tracking this problem with their mice since 2004
, and finally in 2011 a hardware engineer (just a random guy off the Internet) contacted me and told me what the problem was, as well as the details/harmonics involving why it happens. The issue is caused by ceramic capacitors. Simply replacing them with tantalum caps solves the problem. This issue has also begun to affect certain models of Microsoft mice.
I would LOVE if you would really drill Logitech on this one, hard core. As I said, I've been trying to get it solved for EIGHT YEARS
Finally, and I'm going to bold this, because so many people respond to posts of mine like this with "I have Product X and I don't hear what you're talking about": it all depends on the level of sensitivity of one's hearing. I happen to have extremely sensitive ears and quite a large frequency range is audible to me (a colleague of mine used a software tone generator to generate frequencies of pulse/square waves to see where my limit was -- it's something like 8-9kHz higher than the average person). So please do not state something ignorant like the above. This ignorance is exactly why these products emit noise to begin with: the person designing them and the persons QA'ing have normal or sub-par hearing.