Doesn't the bottom fan kill the smooth air flow?

[Metro1337]

I've taken the original image from quietpc (plz don't sue me). My thinking was that as the front intake fans take air in, the bottom fan kills the actual airflow as he blows the "cool fresh air" from the front intakes towards the top, thus the air can't flow "smoothly" over the components to the exhaust. Also, since the bottom intake is not directly under the GPU it shouldn't help with its airflow too, right?

This image might seem a bit confusing at first, but I hope you'll quickly understand what I'm trying to refer too. Red is hot air, blue is cold. CPU is the CPU cooler, and Card the GPU which has no rear exhaust therefore spreads the hot air around the case (mine is the 780 Windforce from Gigabyte). I'm not using top exhaust

How much am I right with that? Wouldn't this completely make the bottom intake unnecessary but only bad for the actual airflow?

Happy new year and thanks for your answers already

 

[USAFRet]

What temps are you seeing at idle and under load?

 

[geofelt]

I don't see a big problem.
Yes, the bottom fans might not be necessary.

The objective of case airflow is to get heated air from the parts out of the case asap.

 

[Metro1337]

What temps are you seeing at idle and under load?

About 35°C in idle and 70° under load (very globally), but it's not about the temps in the thread its about the actual use of bottom fans.

I don't see a big problem.
Yes, the bottom fans might not be necessary.

The objective of case airflow is to get heated air from the parts out of the case asap.

I know what the fans are for, I'm just wondering if my theory about the bottom fan making the airflow worse is true or if I missed something

 

[USAFRet]

The only reason for the fans is temperature control.
Cool air in, hot air out.

An easy way to see if it is better or worse with that bottom fan is to monitor the temp with it, and then unplug it, run the exact same scenario, and see what happens.
Every case, collection of parts, and cable management is a little different.

See what yours does with and without it. Might be better, might be worse.
Only one way to tell...

 

[USAFRet]

In theory, there is no difference practice and theory.
In practice, there is...

 

[Ijack]

You are assuming that you want "smooth" (laminar) air flow to cool the components. This is incorrect. Turbulent air flow provides more efficient cooling than laminar flow.

 

[17seconds]

You are assuming that you want "smooth" (laminar) air flow to cool the components. This is incorrect. Turbulent air flow provides more efficient cooling than laminar flow.

If that's true, then that's a great answer.

@ Metro
This is exactly how my setup is. I think you're assuming the bottom fan "steals" all the airflow from the GPU. Why wouldn't you assume the front fans are stealing the upward draft of the bottom fan? I mean, the front fans may be blowing that cool bottom air back over the GPU, rather than the other way around. I think, ultimately, the difference in GPU temps would be nil if you were to take out the bottom fan. They might even increase since the bottom fan is supplying the coolest air of all the fans.

 

[USAFRet]

Test it, with and without, in your case and environment.
That is the only way to know for sure.

 

[Metro1337]

Test it, with and without, in your case and environment.
That is the only way to know for sure.

I would only if I could, but I only have 4 fans in total (2 intake one CPU and one exhaust on case). Therefore I have to believe Ijack's answer for now.

Thanks to all of you guys!

 

[USAFRet]

Test it, with and without, in your case and environment.
That is the only way to know for sure.

I would only if I could, but I only have 4 fans in total (2 intake one CPU and one exhaust on case). Therefore I have to believe Ijack's answer for now.

Thanks to all of you guys!

Takes 10 minutes to test. Just unplug the bottom fan. See what happens.

 

[Ijack]

Test it, with and without, in your case and environment.
That is the only way to know for sure.

Very true. There are so many factors that can affect the efficiency of cooling that a practical experiment is the only real way to tell.