[geeks] Of video cards and power supplies...

[Nadine Miller]

On Jul 14, 2009, at 2:46 PM, nate at portents.com wrote:

> Since I know some of you have expressed interest in quiet systems, I
> thought I would share the following experiences...
>
> Summary:
> Due to a poor power design in reference NVIDIA cards such as the GTX  
> 280,
> audible squealing and other noises can be emitted from some  
> perfectly good
> power supplies during certain types of GPU load.  ATI cards that use
> digital VRMs such as the HD4850 and HD4870 do not cause any noise to  
> be
> emitted.  I have found that changing the power supply to a design that
> derives the 5V and 3.3V from the 12V in a highly efficient DC to DC
> conversion process, and probably provides greater 12V rail isolation,
> eliminates the noise that a GTX 280 would normally cause.
>
> Details:
> Originally I had a Corsair HX620W power supply, which is a good power
> supply, as detailed in these reviews here:

<snip>

> Alternatively, you could also avoid the problem by using a recent ATI
> card, using a non-reference designed NVIDIA graphics card, or wait  
> until
> NVIDIA will (most likely) adopt a digital VRM solution like Volterra  
> in
> their future reference designs.

Interesting info.  I have the Corsair 850W, and I have this noise  
problem on it with an nVidia 9800GTX+; I also hear increased noise  
when the hard drives are under load.  I was able to mitigate it  
somewhat by using ferrite chokes on the video cables (they are KVM  
cables with USB/audio/video all together--even worse :-/ ) that I  
picked up at the rat shack.  It's pretty much inaudible now at  
"normal" listening levels, but if I have something that has been  
ripped with a low sound level, it becomes much more apparent to my  
ears which are sensitive to higher-pitched noises.

I'll try switching the power cable to the video card and/or adding a  
choke to that cable.  I may also try putting some smaller chokes on  
the sata cables, since I'm noticing it from HDs, too.

I don't know if the box that has the nVidia 250 in it also makes the  
noise as I haven't been using it to play movies or for gaming to any  
real extent yet.

=Nadine=