SweClockers: Geforce GTX 590 burns @ 772MHz & 1.025V

[AtenRa]

The air flow in of the HD6990 isn't like that.

The 6990 fan is a centrifugal fan - that means the air flow changes direction twice - once when entering and second when leaving (forward curved, backward curved or inclined, radial) - the 6990 seems to me forward curved.

The GTX590 is an axial fan - air enters and leaves the fan with no change in direction.

This is exactly the air flow, the only difference is that the air will go side ways directly after leaving the blades of the centrifugal fan (HD6990) when in the axial design of the GTX590 the air will pass through the blades of the fan and in to the bottom of the card (to cool the VRMs) and then it will move left and right in to the two heatsinks. The base plate design is such that drives the air to flow left and right.

Yes the HD6990 centrifugal fan it seams to be a backward curve design.

 

[zebrax2]

*This is all based from my interpretation

If you look at it you can see that when the fluid passes through the smaller pipe pressure start to build up at the larger pipe because air cannot pass through as easily. The pressure is relieved as the air starts to go faster to the smaller pipe. Fluid speed increases because the force pushing it is also increasing due to pressure. This will continue until they come to a certain pressure difference wherein the pressure increase to the large pipe is cancelled by the rapid removal of air through the small pipe . This suggest that the the smaller the the other pipe is the higher the needed pressure difference is as it will need to transfer the fluid at a much faster rate to achieve the same volume transfer rate as that of a larger diameter pipe.

So from my analysis the smaller the exhaust slot is the higher pressure is needed to be generated inside the card. Now if the pressure the fan is generating not enough, the air taken in by the fan would be disproportionate to the amount the card is exhausting (considering only the left side). This would mean that air entering the card then bouncing off the PCB (or whatever it is behind the fan) would more likely to go to the right rather than left as it can accommodate more air flow

 

[GaiaHunter]

No.

In the 6990 the air will be directed to the front heat skin and then pull backwards to the rear and from there exhausted.

In the GTX590 the air is sucked in and will move towards both heath sinks. The air in the rear will be exhausted. The rest will be dumped inside the case.

See the front of the 6990.

 

[AtenRa]

No.

In the 6990 the air will be directed to the front heat skin and then pull backwards to the rear and from there exhausted.

In the GTX590 the air is sucked in and will move towards both heath sinks. The air in the rear will be exhausted. The rest will be dumped inside the case.

See the front of the 6990.

No

The only place the Centrifugal fan sucks air is from the fan opening in the middle of the card.

(correction) I would say the HD6990 fan is Forward curve design and not Backward Curve

 

[GaiaHunter]

No

The only place the Centrifugal fan sucks air is from the fan opening in the middle of the card.

The image you link though is a from a schematic for a blower with a squirrel-cage encasing like this one.

Obviously on this case the air can't be sucked from any other place.

Another thing you need to take in mind is that the 6990 as a bigger exhaust than the GTX590.

Quoting AT article on the GTX590 http://www.anandtech.com/show/4239/nvidias-geforce-gtx-590-duking-it-out-for-the-single-card-king/2

Finally topping the card is a removable shroud that encloses the card to only allow air immediately out of the front and rear ends of the card. Compared to the 6990 NVIDIA has kept their common recessed design, with the shroud & fan being slightly recessed compared to the thickness of the card elsewhere. Compared once more to the 6990, one quirk is that while AMD left a whole slot’s worth of ventilation available on either side of the card, on the external exhaust side of the card NVIDIA only has what amounts to half a slot of ventilation. The other half of the slot is occupied by a DVI connector, meaning the GTX 590 has a smaller external ventilation opening than even the GTX 580, even though TDP is up. As you might expect this means that more hot air is clearly being exhausted inside the case, making effective case cooling even more critical than it was with the 6990.

In the AT article they state

When it comes to cooling the biggest immediate difference from the similarly designed 6990 is going to be the choice of fan. AMD went for a blower, similar to what we seen time and time again on the GTX 400 & 500 series, along with the Radeon HD 5000 & 6000 series. NVIDIA however went with a traditional 80mm fan, which isn’t something we’ve seen on high end cards as of late. In practice the functionality is identical—each blows air out either end of the card. The biggest difference is going to be airflow and noise;

But I also believe air will be sucked through the front of the card due to the suction effect create at the center of the fan, but I might be wrong.

(correction) I would say the HD6990 fan is Forward curve design and not Backward Curve

Yeah I have edited that a while ago.

 

[pcm81]

The fan designs in 590 and 6990 are different.
6990:
http://en.wikipedia.org/wiki/Centrifugal_fan

While 580 does not use cintrifugal fan, it uses propeller fan, which in that particular application is less efficient.
http://www.engineeringtoolbox.com/fan-types-d_142.html

The fan in 6990 pushes air across the heat sinks, while the 590 fan build a high pressure area, right underneath the fan, which causes airflow across heat sinks.

It is interesting to note that the 6990 fan only pushes air across top forward and bottom back halves of the heatsinks, the other 2 halves, have to settle for airflow due to pressure gradient, not a direct output from the fan.

Having taken apart my old 6990 heat sinks, I do not see any airflow mixing elements inside the heat sinks

 

[GaiaHunter]

The fan designs in 590 and 6990 are different.
6990:
http://en.wikipedia.org/wiki/Centrifugal_fan

While 580 does not use cintrifugal fan, it uses propeller fan, which in that particular application is less efficient.
http://www.engineeringtoolbox.com/fan-types-d_142.html

The fan in 6990 pushes air across the heat sinks, while the 590 fan build a high pressure area, right underneath the fan, which causes airflow across heat sinks.

It is interesting to note that the 6990 fan only pushes air across top forward and bottom back halves of the heatsinks, the other 2 halves, have to settle for airflow due to pressure gradient, not a direct output from the fan.

Having taken apart my old 6990 heat sinks, I do not see any airflow mixing elements inside the heat sinks

So the is the front simply exhaust?

Because trying to get that information from reviews seems to be a bit complicated, as in either lack of information or contradicting information.

 

[AtenRa]

It is interesting to note that the 6990 fan only pushes air across top forward and bottom back halves of the heatsinks, the other 2 halves, have to settle for airflow due to pressure gradient, not a direct output from the fan.

Can you say it again plz cause i dint understand what you saying.

Edit:

That's what you mean ??

 

[railven]

The fan designs in 590 and 6990 are different.
6990:
http://en.wikipedia.org/wiki/Centrifugal_fan

While 580 does not use cintrifugal fan, it uses propeller fan, which in that particular application is less efficient.
http://www.engineeringtoolbox.com/fan-types-d_142.html

The fan in 6990 pushes air across the heat sinks, while the 590 fan build a high pressure area, right underneath the fan, which causes airflow across heat sinks.

It is interesting to note that the 6990 fan only pushes air across top forward and bottom back halves of the heatsinks, the other 2 halves, have to settle for airflow due to pressure gradient, not a direct output from the fan.

Having taken apart my old 6990 heat sinks, I do not see any airflow mixing elements inside the heat sinks

Okay, we got someone with the hardware and most likely know how. Time, that is questionable. Is there any way you can assemble the fan with a cover (acting as the PCB) and then turn it on in a smokey environment, or any other method you can think of, to see air flow. That would put this to an end on how the fan works in terms of intake and exhaust.

 

[pcm81]

So the is the front simply exhaust?

Because trying to get that information from reviews seems to be a bit complicated, as in either lack of information or contradicting information.

Front is simply an exhaust. Based on the fan design the fan pushes air across top of the front, but that fan does NOT pull air from the front bottom or push air into front bottom. Front bottom and back top are exhausts due to pressure gradient, front top and back bottom are exhausts due to airflow from fan. Due to the size of the card I would not worry about air being dumped into the case, because it is so close to your front panel. Before I went on water I simply reversed the front pannel fan to suck the card exhaust air out.

 

[pcm81]

Okay, we got someone with the hardware and most likely know how. Time, that is questionable. Is there any way you can assemble the fan with a cover (acting as the PCB) and then turn it on in a smokey environment, or any other method you can think of, to see air flow. That would put this to an end on how the fan works in terms of intake and exhaust.

I can assemble it, but don't have a glass chamber to create smoky air flow.

 

[GaiaHunter]

Front is simply an exhaust. Based on the fan design the fan pushes air across top of the front, but that fan does NOT pull air from the front bottom or push air into front bottom. Front bottom and back top are exhausts due to pressure gradient, front top and back bottom are exhausts due to airflow from fan. Due to the size of the card I would not worry about air being dumped into the case, because it is so close to your front panel. Before I went on water I simply reversed the front pannel fan to suck the card exhaust air out.

Alright.

So now we have all the factors.

And those factors explain the cold spot in the front bottom of the case without having to resort to an exhaust fan in the 6990 review and not in the GTX590.

 

[AtenRa]

@pcm81

Plz see my last post

thx

 

[pcm81]

Alright.

So now we have all the factors.

And those factors explain the cold spot in the front bottom of the case without having to resort to an exhaust fan in the 6990 review and not in the GTX590.

Note that what I refer to the top is the top of videocard, the side fathers asway from motherboard. upping a video of the card's heat sink on you tube, stay tuned.


EDIT:

Enjoy - http://www.youtube.com/watch?v=uzFJ8kbCd04

 

[GaiaHunter]

I was talking about this cold spot.

I'll check the video in a bit.

 

[pcm81]

@pcm81

Plz see my last post

thx

To avoid confusion, let me define the terms.

Top is the side of video card farthest away from the motherboard
Back is the side with monitor connectors.

Now, Fan is in the middle and it looks like based on its design the fan can push air out through Top-Back and Bottom-Front quarters of the card (I had this backwards in my last post). This also coinsides with how the heat sinks are shifted, the one in the back is biased towards the top and the one in the front is biased towards the bottom, where the most air flow is on front and back respectively.

Both heat sinks are exhausts.

 

[railven]

I can assemble it, but don't have a glass chamber to create smoky air flow.

Since we can't build this monstrosity, from your experience of the products is the following plausible and if so on a scale of 1 to 5 how likely:

Because of the length of the card, is the force the fan creates able to exhaust air through the front of the case if there is no obstruction?

Thanks in advance.

 

[pcm81]

Since we can't build this monstrosity, from your experience of the products is the following plausible and if so on a scale of 1 to 5 how likely:

Because of the length of the card, is the force the fan creates able to exhaust air through the front of the case if there is no obstruction?

Thanks in advance.

Yes it can, however having a case fan on the front, reverced to function as a case exhaust fan, rather than case intake fan will really help.

picture of the cards heat sink with my understanding of flow through it:
http://magicmrv.com/fan.jpg

 

[AtenRa]

Yes it can, however having a case fan on the front, reverced to function as a case exhaust fan, rather than case intake fan will really help.

picture of the cards heat sink with my understanding of flow through it:
http://magicmrv.com/fan.jpg

I agree with the picture air flow

 

[railven]

Yes it can, however having a case fan on the front, reverced to function as a case exhaust fan, rather than case intake fan will really help.

picture of the cards heat sink with my understanding of flow through it:
http://magicmrv.com/fan.jpg

Is it not possible that those sections you marked as low air flow, not due to force from the fan, to create a vacuum due to the the rapid shift of pressure from the fan and it's exist points?

 

[AtenRa]

A better representation of the GTX590 air flow

 

[Seero]

A single picture, imbedded with clues and questions, lead to an small scale investigation on something that we think we know how it works. Regardless of who is right, everyone participated will learn something, be it from their own research, or others.

My take is far simpler than you guys. Look at cards that doesn't vent hot air into the case, like 5870 and look at the color. Compare it with the 6990 and it is clear that it dumps a lot of heat into the case. 590 dump as much heat into the case, but there is no cold spot. Yes we can drill into how a fan works, but to me, they both suck air in and vent out from the ends of the card.

To make the case even simplier, have a hair dyer blower air on an object. Both the object an its immediate environment will heat up. If the object itself conducts heat, then heat radiates throughout the object. Cooling one end of that object will cool the entire object. That is how HS works.

Look at the color of the cables going through the cold spot. Not only that heat didn't get transfered towards it, but cables going through the cold spot and cooler throughout the top of the HDD bay. This is an indication of the cables being cooled off through the cold spot without heating it up. That means, heat at the cold spot is being removed.

It is clear that 6990 blows hot air out of the front of the card. Doesn't matter how hot it is, the immediate environment around the vent should heat up. There are 2 cables right in front of the vent with much lower temp. Compare the temp of the cable with the rest of the case, the cables are cooler. Compare the color of the 2 cables to the ones in 590, the cables are cooler.

If the cold spot isn't a source of cooling, it would have heated up. Look at the top left of the case above the case rear fan. It is hotter than the cold spot, and it is far from the vent.

 

[taltamir]

I find both the GTX590 and the HD6990 to have unacceptable venting. Air should all be vented out the back of the case, end of story. Anything else is fail.

 

[GaiaHunter]

A single picture, imbedded with clues and questions, lead to an small scale investigation on something that we think we know how it works. Regardless of who is right, everyone participated will learn something, be it from their own research, or others.

My take is far simpler than you guys. Look at cards that doesn't vent hot air into the case, like 5870 and look at the color. Compare it with the 6990 and it is clear that it dumps a lot of heat into the case. 590 dump as much heat into the case, but there is no cold spot. Yes we can drill into how a fan works, but to me, they both suck air in and vent out from the ends of the card.

To make the case even simplier, have a hair dyer blower air on an object. Both the object an its immediate environment will heat up. If the object itself conducts heat, then heat radiates throughout the object. Cooling one end of that object will cool the entire object. That is how HS works.

Look at the color of the cables going through the cold spot. Not only that heat didn't get transfered towards it, but cables going through the cold spot and cooler throughout the top of the HDD bay. This is an indication of the cables being cooled off through the cold spot without heating it up. That means, heat at the cold spot is being removed.

It is clear that 6990 blows hot air out of the front of the card. Doesn't matter how hot it is, the immediate environment around the vent should heat up. There are 2 cables right in front of the vent with much lower temp. Compare the temp of the cable with the rest of the case, the cables are cooler. Compare the color of the 2 cables to the ones in 590, the cables are cooler.

If the cold spot isn't a source of cooling, it would have heated up. Look at the top left of the case above the case rear fan. It is hotter than the cold spot, and it is far from the vent.

Man there is indeed a fan there for all the cards - it is the intake front fan!

Look at the 6970:

Look at the GTX580:

Look at the 6990 @375W

Look at the 6990 @450W:

Finally look at the GTX590:

Do you know what is the difference between all these cards and the GTX590?

The GTX590 is using an axial fan while all the others use a blower fan.

(And if you look at the top of the thermal image of the GTX590 you will see it is cropped slightly shorter than the 6990@450W and that is why it is harder to spot the intake fan)

 

[Seero]

Man there is indeed a fan there for all the cards - it is the intake front fan!...

Assuming we are talking about the same thing. I am saying that there is a fan at the HDD bay (bottom right) when the 6990 IR graph was done. No other IR graphs have that fan, including 590.

If 590 IR graph does have intake fan too, then something is wrong with the IR graph. The area where the fan is blowing is no cooler than the top where the HDD seats.