Examining the GTX 470 & 480 Cooler Designs

[Hauk]

We heard of last minute changes to GTX 480's heatsink. I believe early leaked pics lacked protruding heatpipes. In any case, there are four heatpipes protruding from the cooler which allow for increased fin surface area. To allow for SLI interface clearance however, the the fifth heatpipe is contained within the cooling shroud. In doing so, fin surface area is reduced:

If we examine GTX 470's heatsink, we see all heatpipes are contained within the shroud, which results in a uniform but narrower fin array. Less cooler, but less heat from the GPU. The end result, two cards that offer very similar temp profiles:

It's obvious nVidia knows how to tailor a cooling design. They estabilished some operating temperatures and were able to design two varying coolers which perform as needed. But, could they have done a better job? Could they have lauched cards running in the 80's instead of the 90's?

We know fin surface area plays a major role in heat dissipation. Can anyone conceptualize an air design that would have offered better thermals? With GTX 480, what if the fifth heatpipe were eliminated and the baseplate were extended in that direction to allow thermal transfer to a [full] fin surface area? Crude drawing, too much partying back in the day:

Also worth noting, they opted for a fairly small diameter fan. In general, larger diameter fans can move more air with less rpms and noise. Take a look at the real estate. Could they have used a larger diameter fan and moved more air with the same or less noise?

Finally, a disclaimer. I realize the cards operate at temperatures deemed acceptable by nVidia. No need to post that fact. This is for those who'd like to see one less negative. Power consumption is one thing, 94c is another.

 

[Skurge]

Why do amd and Nvidia use blower type fans in their reference designs? most custom coolers that come out use the more traditional fans and they are quieter.

 

[thilanliyan]

^They want to get the heat out of the case, which you can't really do with traditional fans.

Looking at where some of the capacitors are, it does not look like they could have used a larger diameter fan. What is designed first...the PCB or the cooling solution? I'm guessing PCB, in which case they did not have much room to work with for the fan.

 

[God Mode]

Because the only way to fit these cards in a dual slot configuration + exhaust hot air out the back is with those stupid squirrel fans.

 

[rodrigu3]

It seems as if temperatures have been less of an issue with the few people that have received their cards early. The highest temp I saw was 85C while overclocking and benchmarking furmark. The tradeoff for these people is many of them run their fans at 100%, but they say the noise is not as overwhelming as reviews have made them out to be. One noted the fans weren't much louder than their case fans. Either way, let's see how the heat and noise issue pans out once more people get their hands on these cards.

And then there's always beasts like this that apparently lower temps by more than 20C.

 

[Hauk]

^They want to get the heat out of the case, which you can't really do with traditional fans.

Looking at where some of the capacitors are, it does not look like they could have used a larger diameter fan. What is designed first...the PCB or the cooling solution? I'm guessing PCB, in which case they did not have much room to work with for the fan.

Good spot on the capacitors. If the pcb was designed first (likely was), a larger diameter fan choice may not have been available. Still a bit of room left though; and what's up with 470's oddly located fan diameter center? Hmm..

 

[thilanliyan]

and what's up with 470's oddly located fan diameter center? Hmm..

I think that reduces some turbulence and hence reduces some noise. More importantly it also gives a "pathway" for the air. Do you have a pic of the actual cover...from that you can probably see it's been tailored so that most of the air is channeled that way.

You can see from this ghetto cover for my hybrid water/aircooling solution I was using (exact copy of the 4870 cover) that it is more open on one side so that the air is channeled that way and there is a bit more pressure since it is a smaller opening which helps get the air out of the case quickly.

 

[Hauk]

Ah. Nice work on that design!

 

[chris89]

This is cool. I was thinking the heatsink design could be a lot better and there is room. They just took the cheap route. Not only is the card too hot but the stock 400 series fan profile is terrible. I'm working on moding my 470 cooler/ heatsink. The issue is the metal part of the heatsink is painted. Which reduces it's thermal conductivty and actually creates thermal resistance. Meaning the heat doesn't transfer to the heatsink from the voltage regulators. They reach 100C no matter how cool the core is. So what I'm doing is removing the paint completely to restore the aluminum's thermal conductivity rating. Which is quite good but its far from easy removing the ultra tough powder coat or whatever pain they used. If the heatsink was bigger it would work better like have the heatpipes/ heatsink fill more room.