Side air duct worth it?

[dornick]

Hello everybody. I've been following these forums for quite a while and finally decided to join. For my system I'm planning on building soon, I've been considering this case, the Codegen 6209, recently featured in the Anand budget case review. I like it cuz of the toolless PCI slots and that side air duct. However, will sucking in air directly for outside the case actually do anything? Or is it completely superfluous? Thanks in advance for any help.

 

[Sqube]

Although I am by no means an expert in such matters, I have yet to see a situation where having more air flow through the case is a bad thing.

 

[hondAS2ooo170]

well first u have to have equal or more exhaust fans to make the intake fan work. when i mean equal or more exhaust fans i meant the flow rate (CFM)

 

[beatle]

It's absolutely worth it. I wish every case had a fan, or at least a duct on the side over the CPU. My Coolermaster Cavalier has a duct over the CPU. As an experiment, I covered it and temps went up 5C within a matter of minutes - and the system was idle!

 

[Tiamat]

side ducts usually promote turbulence within your case. Air flow is not just a function of cfm, it is also the function of where the fans are located and the direction they are spinning. More airflow does not necessarily translate to better heat transport. For instance, when you have more flow in than flow out, your temps will suffer.

 

[dornick]

Thanks all. Looks like the general consensus is that it at least can't hurt. I'll most likely have a couple of other fans working at the same time, and I'll make sure I have the same flow in as out.

 

[Blain]

Air ducts are a great thing!
Don't bother with a pre-ducted case. Buy a case and install an air duct directly over your CPU HS fan intake with something like this.
It will direct fresh, cool air exactly where it's needed the most... into your CPU HS. :laugh:

 

[dornick]

Thanks. As for not getting the pre-ducted case, I'm not a big fan of taking a saw to my computer case side. If you have any other alternatives I'd love to hear em.

 

[Blain]

Maybe something like this to bring fresh air from the front of your case directly to the CPU HS?

 

[Tiamat]

Take a look at the Antec 3000B case at newegg. This case is black, has some tooless features, and comes with a decent side air duct. This case is pretty quiet as well, plus it is relatively inexpensive.

 

[Spike]

Would the duct help much for a cpu fan set to "suck"? I assume it might help a little as that warm air would go out of the case instead of recirculating around, but I assume it would be less helpful then having a fan set to "blow".

-spike

 

[Drostie]

I'm amazed that such poor advice is given.

I forget where I read it, but there was a beautiful article where some reviewers build a system from no case fans to many case fans, and found that the one which cooled the most was not the one with the most fans, but the one with just 2, intake & exhaust.

The physics problem here is well known: Air has a low viscosity, and as such, air flow through a fan enjoys Reynold's numbers far in excess of 4000 -- it's turbulent. When people show you the diagrams of cases with airflow lines, they're showing you what would happen if air underwent laminar flow in the case, which it doesn't.

You don't want to increase the turbulence in the case. A side fan does this, especially because it's blasting air at a flat surface: air to the right of the fan would get circulated between your two intake fans, and is essentially trapped in the case, becoming warmer, soaking heat from your hard drives and from your processor & ram. Then this pocket of air has to gradually follow the pressure gradient out of the case, quite as if there were no fans at all.

What you want is enough fan power to replace the air in your case at a decent rate, and no more. You would ideally have all the fans pointing horizontally across the case... think heatpipe tower HSFs instead of ones where you point a fan straight at the mobo. You also want to keep your case as free of internal obstructions as possible,

Of course, you can ignore my advice for the heatpipe tower HSFs. The fact of the matter is that the xp-120 is the best you've got, and for good OCing you'd need it.

But yeah, side fans are superfluous, and can hurt more than they help.

As far as ducts, I haven't heard whether they help or hurt. Theoretically, they'd do both: they'd render an intake fan useless by obstructing air flow, but they'd provide a direct route for cool air for cooling the CPU. And that's for you, Spike -- you want the duct so that air comes in from the side, cools the processor, and after that you decide not to care about it. The purpose of the side duct is not to fix high case temperatures; it's to make those high case temperatures not affect the CPU.

 

[dornick]

But is the air following the pressure gradient such a bad thing? If the side fan keeps pulling in relatively cool air directly to processor, the warm air is gonna have to get evacuated somehow, right? Even if the flow is rather turbulent, it will have to get pushed out in the end, either by extra exhaust fans or just the pressure from the cool air. As for heating up the hard drive and other stuff, I'm not too worried about those as I will probably be OC'ing and the processor will be my greatest concern.

 

[shira]

Originally posted by: Drostie
there was a beautiful article where some reviewers build a system from no case fans to many case fans, and found that the one which cooled the most was not the one with the most fans, but the one with just 2, intake & exhaust.

This assumes that all components are in one, big compartment. An obvious improvement (and the new case designs are doing this) would be for the PSU to be separated from everything else in the case, with its own front-to-back air flow. That design reduces turbulence problems and segregates the PSU's heat from the rest of the case.

 

[beatle]

Originally posted by: DrostieThe purpose of the side duct is not to fix high case temperatures; it's to make those high case temperatures not affect the CPU.

I was ready to write a long post of disagreement until I saw that. You don't necessarily need a cool case all around. You just need to keep the hot things cool. The non-essential parts like PCI cards and optical drives that probably wallow in the stagnant hot air can take the heat, while CPUs, video cards, and sometimes hard drives, can't.

 

[Mucker]

Extra hole = extra noise exit. Personally, I don't like them. You just need to get a case with a 120mm fan in the front and rear and keep the airway as clear as possible of wiring and cabling between the two 120mm fans. AND, with the PSU drawing good airflow, heat will never stand a chance in a case like that........

m

 

[dornick]

Thanks for the Antec 3000 suggestion. I checked it out and it looks pretty nice, though a bit more expensive than I was planning