Yes heatpipes do work, they are very effecient. And no it cannot defy gravitiy lol. Can you snap a pic of the area so we can get a better understanding?

pink

 

As long as your cpu isn't literally facing the floor, heatpipes should work well. There are heatpipes on two sides so half of them are bound to work.

Was the old hsf seated incorrectly? Too much/too little thermal paste? Things can go wrong mounting heatsinks...

 

Yes, they do function very well because of the core. That my understanding of it.

 

Ok, this is what i am talking about....see how the heatpipe goes down from the contact point with the cpu. I dont konw if this is an effective heat transfer and looks to be much more inefficnet than the zalman...

 

... I have an xp 120, mounted sideways, trust me they work, and are effective cause its a liquid under pressure.

 

Quote:

Originally Posted by Blue_Fire Yes, they do function very well because of the core. That my understanding of it.

Yeah i know that the core is there and thats what i am talking about, and i thought (I could be wrong) that it worked like evaporation of hot "Core" up the heat pipe because hot air (I know its not air but same principle) rises....ne thoughts?

Here is the link that made me question the effectiveness in a horizontal position

http://en.wikipedia.org/wiki/Heat_pipe

 

Yes but its a liquid, so the liquid gets hot, runs out of the core and raises to the fins(they are colder) then as it gets cold it seeps back into the core and flow toward the cpu again, think of like 7th grade science how they taught about convection in boiling water.

 

Quote:

Originally Posted by Blue_Fire Yes but its a liquid, so the liquid gets hot, runs out of the core and raises to the fins(they are colder) then as it gets cold it seeps back into the core and flow toward the cpu again, think of like 7th grade science how they taught about convection in boiling water.

hmmmm......7th grade.......

Gotcha! I see what your saying thanks for the knowledege! I will sleep better tonight, lol

 

lol

 

So what about the Zalman VF900 on a gfx card? The entire cooler is pretty much always upside down...

 

It's not that simple, and you have to keep in mind that IT IS the best way when the heat-pipe works as hottest point lowest and the cooling highest. Otherwise it relies on capillary action.

Here is some more info:

Quote:

Originally Posted by Click For Link Vertical orientation required - In our simple model heat pipe, the working fluid simply drips back to the heat source. It is quite obvious that this design will only work in vertical orientation. To overcome this limitation, commercially available heat pipes do not rely on gravity alone to move the liquid back to the heat source; they take advantage of capillary action. The inside of the heat pipe tube is filled with a capillary structure, often referred to as wick. Different structures are being used: The most simple structure is a grooved tube. Here, capillary action merely helps gravity; vertical orientation of the heat pipe is usually still required. Most commonly used, due to better capillary action, is a multilayered metal mesh. Sintered powder capillar structures allow the stronges capillar action, but are more expensive to manufacture. Even with this design, performance of the heat pipe still depends on the orientation, and upside-down operation usually still isn't possible.

 

so to be the MOST effective, you should have it in a vertical position? i wonder how much gravity is working aginst the heat pipe when its on its side?

 

Simply put, quite a bit. I got about 10c on the VF900cu's on load when i layed my case down, and the cpu on load went down about 4 c.

 

^^^ I took off that crap ASUS (stick to making boards) heatsink and my temps went WAY down. I think it was a combo of crappy fan and the heat pipes

 

Think of it like this. When you swallow food, it doesnt matter whether you are upright or upside down, the food still travels into your stomach. Once the liquid evaporates, it'll go whever it needs to get out of the pipes

 

^ OK but your not as efficent when your digesting food upside down, gravity is working aginst you. Thats why i brought this up, my heatsink didnt work too well until i got one without the heat pipes. They do work, i am not questioning that (i konw the title is misleading), but how effective are they when they are horizontal? Oh yeah, and hot air does not have the assistance of muscles, hot liquid evaps up. IMHO, the capaliaries can only do so much. If you boiled water, you could pipe the evap down but it would not be that effective, it would still bottle neck at the highest point and evap there. I really dont know if i am right, this is just my theory.

 

Eh if they are horizontal, that just means its moving slower to the fins. so yes you are correct under ideal conditions they will operate better vertically. But they are tested to run run sideways, also how does fluid move? or air? from high pressure to low pressure. Moving fluid has less PSI than still water, it also has less pressure, here is a link to explain bernoulli's principal in a little more detail.
http://www.ccmr.cornell.edu/educatio...x.html?quid=69

 

My VF900 is mounted usipde as all GPU HSFs are and I still get 35C idle temps... I still have to see why I went fron 58C idle to 35C idle.

 

^ Noice!

 

One thing I will say about a CPU HS is that most are probably manufactured for horizontal use. As 99% of CPU placement is horizontal. So I am sure the calipers inside the heatpipes are fixed for use this way.

pink

 

Nope, they cant be "fixed". Capillaries are used to help gravity. The vf900 is engineered with some really good capillaries, that's why its so expensive and works so well upside down. But when I flipped my case upside down it dropped 10c under load. Mind you that I only ran atitool for 3 min if that compared to the usuall all nighter, because I had to hold 1 fan that usually sits on the bottom of the case pointing at the cards.

 

What I meant by that is when I got ATI Tool 0.25 Beta 14 it showed 35C when 0.24 showed 58C

 

hmmmmm thats odd

 

It works better because heat travels up. You put your case upside down therefore flipping the graphics card upright. The heat can move upward freely faster so it will cool better.

 

I used to say the same thing about heat, too... However, "heat" doesn't always travel "up." Within a solid, heat travels equally in all directions. In liquids and gases, the warmer substance rises above the cooler, more dense substance, whether it's air or water. This process is called "convection." Vaporized water, being less dense than liquid (having less mass per unit volume and therefore less weight) isn't pulled as strongly by gravity and therefore the water drops while the steam/vapor rises above the more dense liquid.