Why is all cooling out the back when heat rises and putting PC with psu output and fan output on top
- Thread starter Grafter67
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As Hotwired said, fans greatly over-power any effect the result of warming of and expansion of air causing it to rise can create. Heat does not rise, but warming air causes it to expaand and be lighter then surrounding cool air .. and thus rise. But the effect is minimal. For example a campfire warms the air much faster and much more then the air is warmed in our computers, yet setting on a log several feet from fire we still get smoke in our face from time to time .. but we always feel the warm of heat being radiated in all directions from the fire. 
My case does blow the heat out the top...
....Try googling for Silverstone FT02 ...http://www.fudzilla.com/component/k2/19585-silverstone-fortress-ft02-chassis-gets-reviewed?showall=1
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So? Your case has fans pushing air from bottom to top instead of front to back. Point is case airflow is being done with fans and not the myth 'heat rises'.My case does blow the heat out the top...
http://www.fudzilla.com/component/k2/19585-silverstone-fortress-ft02-chassis-gets-reviewed?showall=1
Doyll is right. It seems counter-intuitive but convection currents from PC components are not that powerful. Even a slow rotating fan can easily overpower them and drive the warmer air in a direction it doesn't want to go. It is more efficient to drive warm air upwards, but the difference is tiny.
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Airflow from front to back is usually compromised in 'normal' cases, drives at the front usually restrict the flow and the fan area itself is limited.
One of my cases is a Silverstone Raven 2 which I've had for quite a long time (8 years!), the 90 degree rotation of the motherboard has another advantage, no video card sag.
One of my cases is a Silverstone Raven 2 which I've had for quite a long time (8 years!), the 90 degree rotation of the motherboard has another advantage, no video card sag.
If memory serves, the 90 degree rotation used by Silverstone is patented .. which is why they are the only one with this design.
Not all video cards work with 90 degree rotation, especially the 3x fan long ones. Their heatpipes have problems wicking coolant back up the long pipes.
Not all video cards work with 90 degree rotation, especially the 3x fan long ones. Their heatpipes have problems wicking coolant back up the long pipes.
Soldato
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With fans it’s more about having a clear airflow through the case. Most tower cases have better air flow front to back as Gpu etc do not block the air flow. Heat does rise but effect of 140mm fans is far, far greater at shifting heat out of the case even at low rpm.
Front to back airflow with motherboard in normal orientation works best to keep primary heat sources (CPU & GPU coolers) exhausting heated air into an airflow that moves heated air away from cool air source and thus keeps it from contaminating this cool airflow to components. Cases with good front intakes few or no optical drives / HDDs) and tower CPU coolers this works very well, but GPU coolers are horrible (spawned by the heat devil) with the only directions they don't discharge heated air is fan side and back of their PCB .. but with some work like removing all PCIe back slot covers to increase rear vent area around GPU and sometimes a divider fit between GPU and CPU from middle of CPU cooler to front of case we can keep it's heated air moving back and out without contaminating and warming the cool intake air very much.
I've even experimented with 3x flow channels; 1 to CPU, 1 the thickness of GPU to catch heated air off of it going toward front of case and toward motherboard, and 1 to flow cool air to GPU fans .. on thick GPUs this worked quite well.
I've even experimented with 3x flow channels; 1 to CPU, 1 the thickness of GPU to catch heated air off of it going toward front of case and toward motherboard, and 1 to flow cool air to GPU fans .. on thick GPUs this worked quite well.
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Ah, that explains it! I wondered why no-one else was doing it.
I can't seem to find anything definitive either way on this.
I'm running a 290x and a 1080Ti, both are 3 fan cards and they don't seem to be affected by orientation (they aren't hotter than I expected them to be under load, I haven't actually done a proper comparison). I used to run a GTX260 3 fan card as well in this orientation, seemed alright, but again, not a scientific study.
I agree, they are generally terrible. The situation is now beyond a joke, I don't know why the manufacturers are trying to limit their size to 2 slots when that would mean the fans are up against the neighbouring card if there is one (thus isn't practical), and if there isn't one, that space would be better used to move heat away, so why bother? The 2 and a bit slot width cards even more so, they can't even pretend to be able to fit cards 2 slots apart yet waste almost the entire next slot with nothing to show for it.
It depends on what type of wick is in the heatpipes, and I can thing of at least 6 differnt kinds. One I know is problematic is axial groove wick. I think most heatpipes used in our computers now are using sintered metal wicking, and it's capillary action works over longer vertical lengths.
I hear arguments that motherboard PCIe placement standard is the problem, but I think that using a single very powerful GPU is much better then running multiple GPUs for most of us, so why not give us good 3x or 4x slot wide GPU cooling? At least we could have good cooling on single GPU applicatons. There are a few aftermarket GPU coolers that work very well with 3x to 5x PCIe spaces. Even the 2+ wide GPUs need at least 1 more PCI space to have decent airflow to their fans .. and I like having a blank space or two between GPU and CPU too.
PugetSystems did horizontal versus vertical case orientation testing and found no significant difference. If case has good airflow it works either way.
https://www.pugetsystems.com/labs/articles/Vertical-vs-Horizontal-Case-Cooling-89/page2
It depends on what type of wick is in the heatpipes, and I can thing of at least 6 differnt kinds. One I know is problematic is axial groove wick. I think most heatpipes used in our computers now are using sintered metal wicking, and it's capillary action works over longer vertical lengths.
I hear arguments that motherboard PCIe placement standard is the problem, but I think that using a single very powerful GPU is much better then running multiple GPUs for most of us, so why not give us good 3x or 4x slot wide GPU cooling? At least we could have good cooling on single GPU applicatons. There are a few aftermarket GPU coolers that work very well with 3x to 5x PCIe spaces. Even the 2+ wide GPUs need at least 1 more PCI space to have decent airflow to their fans .. and I like having a blank space or two between GPU and CPU too.
PugetSystems did horizontal versus vertical case orientation testing and found no significant difference. If case has good airflow it works either way.
https://www.pugetsystems.com/labs/articles/Vertical-vs-Horizontal-Case-Cooling-89/page2
If you get one of the top cards like 1080ti from Asus or MSI, the cooling is extremely good, my 2.5 slot Strix 1080ti rarely goes over 60c with almost silent fans, I don't think 3-4x pci slot height cards are necessary and also they would sag! It is at the point with these cards where adding water cooling is a minor difference.
I've found bottom intake often helps supply GPU with cooler as long as the is enough rear vent to let all GPU heated air out .. which is why I always remove all PCIe back slot covers. This greatly increases rear vent area and allow front to back airflow around GPU. But top venting is usually too far toward back of case for good air flow to front of CPU cooler, so rarely helps, and we do not want bottom to top airflow because this moves so much of GPU's heated exhaust air up around CPU cooler causing higher CPU temps.
I'm still running one of the 3x slot Asus DirectCU II Series GPUs and believe me it's needs 5 slots ot work properly. If memory serves, PCIe sockets are spaced 20.2mm or 22.2mm, and 80-92mm fan/s needs about 25mm on all sides to for good airflow .. and if side by side with only one side open like on GPU with a at card a couple slots below it, they need 2-3 times as much space to have similar airflow cross-sectional area as fan for needed airflow.
Any of the big card benefit from support to keep them from sagging,
When I say 4-5 PCIe slot card I refer to total area needed for card and airflow to it's fans. A GPU that is occupies 2.5 GPU slots needs that additional 2-2.5 PCIe slot space for airflow to it's fans.
I'm still running one of the 3x slot Asus DirectCU II Series GPUs and believe me it's needs 5 slots ot work properly. If memory serves, PCIe sockets are spaced 20.2mm or 22.2mm, and 80-92mm fan/s needs about 25mm on all sides to for good airflow .. and if side by side with only one side open like on GPU with a at card a couple slots below it, they need 2-3 times as much space to have similar airflow cross-sectional area as fan for needed airflow.
Any of the big card benefit from support to keep them from sagging,
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PugetSystems did horizontal versus vertical case orientation testing and found no significant difference. If case has good airflow it works either way.
https://www.pugetsystems.com/labs/articles/Vertical-vs-Horizontal-Case-Cooling-89/page2
Nice link
It's down to preference/area constraints really, tho it isn't easy to find a case with all that fannage at the front (and the rotated silverstone range is still too limited imo).