Air flow question

cichy1012

So heres what I got. I have:
Geforce 1080 ti 11gb founders edition (fan as and exhaust)
120 mm 1500 rpm fan on back exhaust
Noctua nh d15 for cpu
2 120mm front intake fans
1 120mm on the bottom of case where the hard drives would be.

im at 29.65 at idle  (if this is an accurate program)

should i be adding top exhausts?

crankked

I have my I5-3570K OC to like 4.4ghz.  I idle at around 25-30C and I have half the fans you do.  I don't think I would worry about it.  

Check the temps when you are gaming and see how high they go and if it stays within acceptable limits.

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cichy1012

crankked said:

I have my I5-3570K OC to like 4.4ghz.  I idle at around 25-30C and I have half the fans you do.  I don't think I would worry about it.  



i think 44 is the highest ive seen

Quizzical

It's really not very hard to cool a mid-tower gaming desktop with a single GPU, so long as you aren't running an unreasonably large overclock.  The main benefit to having a lot of fans is that you can run them slowly and keep the computer quiet.  As far as temperatures, you likely would see some measurable benefit to adding top fans, but the temperature difference won't make any practical difference.  If your CPU and GPU are consistently under 80 C, they're fine and not worth worrying about unless you're doing something unusual.

The main ways to mess up airflow are:

1)  Having far too little space, such as a laptop.
2)  Having far too large heat output, such as a densely packed rack full of servers.
3)  Having something physically block the intended airflow path, such as if the back of your case were up flush against a wall so that no air could exit your intended exhaust point.
4)  Having fans die, especially if you have a single case fan and it dies, so that you have no case airflow.

Points (1) and (2) are manageable, but need to be handled carefully.  There are sound reasons why those aren't viable enthusiast projects to build your own from parts.  A mid-tower gaming desktop with a single video card is emphatically not either of those cases.

On point (4), if you have four case fans and one of them dies, it's really not a big deal.  If you have a single fan for your CPU, GPU, or power supply and it dies, you could end up with that one component getting too hot, even as everything else remains fine.  But the worst case is having a single case fan and then it dies, so that you have no case airflow at all apart from a little bit from other fans only intended to get heat off a single component.

Vrika

No. Add fans based on max. temperatures, not idle temperatures.

Also at least your GTX 1080 ti fan should adapt its speed based on GPU temperature, so it'll push more air out of the case once it heats up.

Quizzical

Vrika said:

No. Add fans based on max. temperatures, not idle temperatures.

This.

The main reason to look at idle temperatures is if you suspect that something is severely wrong with your cooling, such as not having a heatsink on securely or having a heatsink so clogged with dust that air can't go through it.

cichy1012

thanks all. always helpful

Ridelynn

Looks good to me. 29C is just barely over what most people keep ambient. So long as your full load temps are in line (GPU <85C, CPU <95C) your perfectly safe. You can get better boost clocks if you can hold the temps significantly under that, but looking at your setup, I don't think any more fans will help you out any in that regard - the setup looks pretty good with respect to air flow.

Cleffy

I don't think you need additional exhaust fans. You have a positive pressure airflow which is ideal for keeping dust down. I don't think making it more neutral with additional exhaust will do much to increase airflow. I would only add the exhaust fans if you are using it with a radiator.

Connmacart

To improve airflow, what you really need is a different case. Correct me if I'm wrong, but it looks like you have a Fractal Design Define C. This is not an airflow case. The front panel, unless you removed it, will limit your front intake. That bottom fan doesn't do much due to the power supply shroud that is blocking air to the rest of the case.

You probably already have maxed out what you can do in that case. The only thing could be replacing the stock fans for better ones.

Vrika

DMKano said:

What is the ambient air temperature?

This is the #1 thing people overlook.

Is the PC sitting in a room that is hot already?


When it comes to air cooling - All the best airflow isnt gonna do shit if the ambient temperature is already hot.


Drop the air temperature in the room to below 70 degrees Farenheit and you will get much better air cooling results.

Ambient temperature doesn't really matter. It looks nice in idle figures, but if something is running too hot then it's so much hotter than ambient that the ambient doesn't matter.

Quizzical

Vrika said:

DMKano said:

What is the ambient air temperature?

This is the #1 thing people overlook.

Is the PC sitting in a room that is hot already?


When it comes to air cooling - All the best airflow isnt gonna do shit if the ambient temperature is already hot.


Drop the air temperature in the room to below 70 degrees Farenheit and you will get much better air cooling results.

Ambient temperature doesn't really matter. It looks nice in idle figures, but if something is running too hot then it's so much hotter than ambient that the ambient doesn't matter.

That depends on how much the ambient temperature can reasonably vary.  For a desktop in a room where people live, the answer is usually not very much, so I agree with you, provided that the end user doesn't do something stupid.  I once caught my sister pointing a space heater at the air intake to a desktop, and that can make the ambient temperature hot enough to matter.

For things that are placed outdoors or in a data center where the temperature can be set to the preferences of hardware rather than humans, the difference between an ambient temperature of 5 C versus 50 C can matter quite a lot.

Ridelynn

I'd say if he's running at 30C idle, that pretty much answers your ambient question right there, unless you want to assume something extreme, like him living in an igloo or sticking the PC in an icebox...

Ridelynn

Vrika said:

DMKano said:

What is the ambient air temperature?

This is the #1 thing people overlook.

Is the PC sitting in a room that is hot already?


When it comes to air cooling - All the best airflow isnt gonna do shit if the ambient temperature is already hot.


Drop the air temperature in the room to below 70 degrees Farenheit and you will get much better air cooling results.

Ambient temperature doesn't really matter. It looks nice in idle figures, but if something is running too hot then it's so much hotter than ambient that the ambient doesn't matter.

It won't be exactly one to one, but will have an effect. If you raise your ambient by 5 degrees, all your temps will rise by some smaller amount. Energy transfer deals mostly with differences between temperatures, phase change notwithstanding, not so much the absolute temperature itself.

Now, a lot of HSFs, AIB slot coolers on GPUs, and laptops utilize heat pipes, which do have a phase change element to them, and that will greatly stabilize that heat transfer because the phase change itself is going to burn a lot of that energy. A heat pipe can be designed to operate at a specific temperature based on what pressure (vacuum actually) and fluid is inside the pipe. Once the heat pipe hits that temperature it will become super efficient as the phase change starts to take place, and will stay that efficient until you finally saturate it (basically boil/wick all the liquid faster than it can re-condense and fall back down). 

It takes a lot of energy to get a heat pipe to saturate beyond that working temperature, but it could be done if, say, the fan failed or the fins are clogged with dust or your trying for a massive overclock on an undersized HSF. A standard heat pipe operating within it's design envelope will usually be robust enough to absorb/mask any change in ambient temperature.

But if you are working with a water cooled loop or direct contact heatsink blocks (Intel stock cooler, most RAM heatsinks, VRM heatsinks, etc. come to mind), and heat pipes before they hit their magic temperature (or after you saturate it) - it will be close to a 1:1 temperature change with ambient.

Another effect that will mask that - variable speed fans. You will only see the ambient 1:1 effect if your fans are set to a static speed. If your fans are able to adjust speed, they will do so, and you probably won't see a difference in temperature, but your fans will ramp up/down with ambient to absorb the difference there. It wouldn't be much, so probably not even noticable unless you were looking at long term graphs (or your fan hits some harmonic and starts making an ungodly racket at certain RPMs)

It can mean the difference between a borderline overclock or a silent build working or not, but I do agree, in stock situations your cooling should be adequate enough that it isn't going to matter. Most systems are designed so their heat pipes (or sinks) are well oversized, and they modulate the fan to a target temperature. Only  should you hit 100% fan speed (or you are concerned about the noise of your fans are making ramping up) and still not be able to control temperature - that's the point you really need to worry about your cooling.