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View Full Version : 6800 Series AS Guide, Buzzing Fan Fix


Fatman
10-13-04, 07:35 PM
It took me a while to gather all this up and post it, I hope some of you will find this useful.

Here is a basic walkthrough for replacing thermal grease on the GPU and getting rid of the crappy thermal pads. Supposedly all reference design Ultras use Arctic Silver thermal compound. I thought so too until I removed GPU heatsink. Whatever that was, it was pretty chunky. Thermal pads are even worse. Thermal pads are made with phase change materials, usually some soft of wax that "melts" at a certain temperature. The pads on the Ultras do no change phase, they remain in their original form, oily white squares. Nasty stuff. So here is the basic info:

Speciment: PNY 6800 Ultra - Reference design.

Tools required: Various sizes Phillips type screw drivers, and an extra pair of hands.

And remember, there are no "extra" parts.

6 tiny silver screws holding the heatsink assembly cover.
4 silver screws with springs holding the GPU aluminum heatsink.
5 Black screws with springs hold the ram heatsink from the back side of the card.
3 smaller silver screws hold the plastic fan housing from the back side.


Start by removing 6 tiny screws that hold heatsink/fan assembly cover. Phillips type screws are very small, about 2-3mm long with flat tops, about 1mm across. Once the cover is off, you will notice the aluminum GPU heatsink, ram heatsink, and plastic fan housing holding it all together.

Flip the card over, and on the back side look for 3 silver screws about 2.5mm. They should be arranged in the triangle like configuration, closer to the output panel. Removing them will allow you to take off plastic fan housing unit.

Now you should be looking at the GPU heatsink and ram heatsink wrapping around it. Ram heatsink is held in place by 5 black screws with tension springs, on the back side of the card. Remove the heatsink, and take off the thermal pads. Looking at the underside of the ram heatsink you will notice rectangular blocks. They are raised about .5mm off the surface and polished. These are the areas of the heatsink that make contact with ram chips.

Now the only thing left should a big chunk of aluminum covering the GPU. It's held in place by 4 silver screws, with tension springs. Removing them, will expose the GPU.


BFG, PNY and probably most other reference design Ultras already use what appears to be Arctic Silver thermal compound. However, when I examined the leftover compound, it was clear that it was lesser quality than retail Arctic Silver compound. In fact, it was pretty chunky and grainy to the touch. Clean the contact areas of the heatsink with a clean, dry cloth. If you have isopropyl alcohol, you might want to give it a once over, just to get rid of that extra layer of gunk. Now, apply Arctic Silver thermal compound to the GPU and ram chips. Although the compound is non conductive, don't go overboard, use a small amount of the compound on the GPU, and even smaller amount on the ram chips. I prefer to dab & spread, some may prefer to spread the compound evenly across the entire surface. In ether case, once the heatsinks are mounted, press forcefully, yet gently and evenly to get rid of any possible air pockets. On the GPU itself, press down, and give it a 45 degree twist. In my own experience it spreads the compound very evenly across the top of the heat spreader.

The next step will probably require another pair of hands. Grab the X shaped back plate. Align it with holes, and while one person is holding on to the GPU heatsink and the back plate, secure it with screws. Secure one screw, then go diagonally across to keep the pressure at similar level, and don't tighten the screws just yet. For now you just want to secure them in place. Once all 4 are mounted, you can start tightening them. Once again, don't go nuts, and use common sense, not too loose, not too tight.

Once the GPU heatsink is on, mount the ram heatsink, and secure it on the backside with 5 black screws. Once all 5 are secure, tighten them up evenly across the whole unit. Since the thermal pads are off, make sure the ramsink makes contact with ram chips. You might need to tighten the screws a bit more to ensure good fit.

Mount the fan housing, secure with 3 silver screws on the back side of the card. Don't forget to reattach the fan power. Put the cover back on and you're done.

Buzzing fan fix.

So far I've had 2 reference design 6800 Ultras, from different manufacturers that were making a buzz-saw like sound upon powerup, before the Windows drivers kicked in and scaled back the RPMs. This particular PNY sample had the same issue, and the fix for it as you can imagine is very simple. Remove 6 tiny screws, and take off the cover. Looking at the picture you will see where the fan was making contact with the cover. You will see that the ring around the intake hole is raised. Simply push back on the area which is making contact with the fan with your thumbs. Put the cover back on, and holding it in place make sure the fan has enough clearance. Another, even easier fix is to let the fan grind down enough clearance for proper operation. But how fun would that be!?


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Fahim
10-14-04, 08:47 AM
Thanks........great post.