Several threads are present on this throughout the web, but I haven't come across any here.
The solutions to this problem regards disabling Power Saving modes by one way or another in order to prevent noise (such as using RMclock or plugging in a USB device). Bad. Very Bad engineering folks. Turn power down... turn noise up.
This problem is known to affect many Macbooks, dells, and HPs (and probably others). The Core 2 Duo seems to be the greatest offender - but this is probably a coincidence due to the popularity of this chip these days.
Well, here are the links. A preliminary list.
I think this issue is somewhat newsworthy, I've heard very little about it officially other than a obscure issue hidden deep in the support pages of dell/apple.http://forum.tabletpcreview.com/showthread.php?t=3516 Main Fix from RMclock
Link to various threads
http://forum.notebookreview.com/showpos ... stcount=12
Here is actually a very good article on dell's site about this issue:
http://support.dell.com/support/topics/ ... en&s=gen#2
On a personal note, this far, I've heard this on Dell 6400 and 9400 models. I was never to suppress the noise fully on the 6400 using techniques described above, I think it has a difference problem altogether (maybe that's why they don't offer that laptop with the T7400 anymore??)1. An audible high pitched buzzing noise is emitted from the notebook.
When the notebook is used in a quiet environment, an intermittent high frequency buzzing noise may be heard from the system. It appears to change with processor activity and can increase in amplitude if USB 1.0 peripherals are attached. It can also vary between platforms depending on the installed devices and system specifications.
The buzzing noise is apparent to some degree on all notebooks, but is perceived as abnormal because it is different from other more familiar noises generated by the notebook.
The noise has been isolated to the processorâ€™s power circuit and is only audible when the processor is in C3 (clock-stopped) power state. In C3 power state, notebook power is conserved resulting in reduced overall chassis heat and extended battery life. The varying voltage changes to the components in the processor's power circuit are caused by a phenomenon referred to as the piezoelectric effect. When a specific varying voltage is applied to these components, they begin to resonate producing sounds that fall within the frequency range of human hearing (15 â€“ 20 KHz).
The level of the noise is within the acoustic specifications of the notebook and well below other noises from components such as the system fan and the hard disk drive.
With the 17" dell 9400 the Noise is also present, seemingly a little less noticeable. I seem to able to turn it off (at least to 99%, or maybe that's in my head ) using RMClock. Will try some other methods.
I've also seen this noise occur on one of toshiba's latest, a Core 2 1.66Ghz with Geforce 7600 Graphics (toshiba A100-VA9)
Also, a friend's Acer (Pentium M) also appeared to suffer from this problem.
EDIT: lol just found these on youtube... enjoy (turn your speakers up)
EDIT #2: Here's the latest from HP. Looks like they've stepped up, somewhat.
http://h10025.www1.hp.com/ewfrf/wc/gene ... R1002_USEN
EDIT #3: The only trick that has ever worked for me was "run HLT command when os is idle" in RMclock.