Video Card Fan

Did the other replacement fans help with noise?  Unless they are making grinding, mechanical noises, a new fan will run the same speed as the old fan did, with the same sound.  You don't want it slower, that compromises cooling.

 

Video card fans are flimsier than case and heatsink fans, so they do tend to fail more readily.  But if all it's doing is the z-z-z-t sound from running fast, replacing it is not likely to achieve much.

The fan really "revs" like it's ready to take off.  Sometimes it stops when I reboot - sometimes I have to shut down a while to make it stop.  Then a week or so it starts again.

Video card fans are typically two-speed.  Slow, on desktop.  Fast, when the graphics engine is called upon to do advanced display work.  Some may actually sense the chip temperature.  8400 is old enough to have accumulated substantial dust which acts as insulation and raises chip temp.

 

But if you have already cleaned out the case internals thoroughly, and this is a new symptom that wasn't present originally, the problem doesn't fit an identifiable pattern.  The video card fan is under control of the card itself, not any Dell hardware.  So if you are certain it is the video card fan making the noise (stop it with your finger and see if the noise abates), the card may have a problem.  The fan is replaceable but it will take some research.  Go to the vendor's site, either Nvidia or the brand name on the fan.

Since I'm still under warranty, and since Dell themselves suggested that it could be the Video Card Fan making the noise since all other fans had been replaced - I'm hoping that is the final problem with this 8400. 

 

They e-mailed the a diagram of the inside of the hard drive and my son is going to check it out next weekend with them to see if removing that stops the noise and then they will probably send someone out to fix it before the warranty expires.

 

I was just curious to see if I was the only person who had many fans replaced since getting the 8400.

 

Thanks for your input.  It makes it clearer.

 

You're welcome.  Backstory sometimes helps.  Didn't know you had warranty, that should clear it up.