Block off unused vents?

[scannall]

Just a simple question. Towards the rear of my case are two openings made for a pair of 120mm fans. I don't have fans there currently. I have a front fan, and a rear exhaust fan. Also a big heat sink with two 120 mm fans on it.

Should I block off the two large holes to get better airflow through the case? It isn't running hot or anything like that, I'm just trying to get the best out of what I have.

 

[T_Yamamoto]

Just a simple question. Towards the rear of my case are two openings made for a pair of 120mm fans. I don't have fans there currently. I have a front fan, and a rear exhaust fan. Also a big heat sink with two 120 mm fans on it.

Should I block off the two large holes to get better airflow through the case? It isn't running hot or anything like that, I'm just trying to get the best out of what I have.

Don't block it. It'll just raise temps

 

[janas19]

Don't block it. It'll just raise temps

The temps are controlled by the ambient air blowing in.

If you block the holes, it will make your exhaust fan more efficient. But you may also see your case temps going up, if you don't have adequate intake. I would block them off, then see if temps change.

 

[scannall]

The temps are controlled by the ambient air blowing in.

If you block the holes, it will make your exhaust fan more efficient. But you may also see your case temps going up, if you don't have adequate intake. I would block them off, then see if temps change.

Thank you for replying. I appreciate it. I am kinda hoping to make the airflow more efficient through the case and also quiet it. The intake fan has a nice clear route, as does the exhaust. I am hoping to put a layer of foam inside the case to quiet it down. I get tired of hearing it.

 

[janas19]

Sure, glad I could be of help!

 

[MontyAC]

Leave the holes unblock and have positive air pressure for your case.

 

[janas19]

Leave the holes unblock and have positive air pressure for your case.

No, positive air pressure means essentially more air is entering than exiting.

If you have "holes" it will create negative air pressure, if anything.

There is somewhat of a debate on the net of PAP vs NAP. PAP will keep dust out, and also allow your fans to rotate at lower RPMs. However NAP can expel hot air more quicker.

Personally, I think the best setup is an adequate HSF and PAP.

 

[T_Yamamoto]

No, positive air pressure means essentially more air is entering than exiting.

If you have "holes" it will create negative air pressure, if anything.

There is somewhat of a debate on the net of PAP vs NAP. PAP will keep dust out, and also allow your fans to rotate at lower RPMs. However NAP can expel hot air more quicker.

Personally, I think the best setup is an adequate HSF and PAP.

potato potato (you know what it should sound like)

 

[slpnshot]

No, positive air pressure means essentially more air is entering than exiting.

If you have "holes" it will create negative air pressure, if anything.

There is somewhat of a debate on the net of PAP vs NAP. PAP will keep dust out, and also allow your fans to rotate at lower RPMs. However NAP can expel hot air more quicker.

Personally, I think the best setup is an adequate HSF and PAP.

Sorry but what is a HSF?

I currently have an Antec 300 with an unused side fan-slot. I'm wondering if I should just get a cheap filter to 'close' it off from dust or actually get an exhaust fan for it.

 

[janas19]

Heatsink/Fan aka cooler

 

[lsv]

Try it out, I've blocked off my top exhausts and side intake on my R3 because I do not want excess noise but I can deal with the higher temps.

 

[bluesky]

An interesting read here.
http://www.eggxpert.com/forums/thread/518908.aspx

I happen to be running a rear exhaust fan only except HSF in my case.
Yeah, a lot of dust in the cracks.

 

[Sunny129]

No, positive air pressure means essentially more air is entering than exiting.

If you have "holes" it will create negative air pressure, if anything.

this isn't true either...

PAP and NAP can only be achieved in a fairly well sealed case, where the only places air can enter and exit the case are through the intake and exhaust fans/ducts, and nowhere else. it doesn't matter whether intake CFM > exhaust CFM (PAP) or intake CFM < exhaust CFM (NAP)...if there are uncovered holes elsewhere in the case, any positive or negative pressure that might otherwise be induced by the arrangement of case fans will be negated by those holes. open a hole in the case of a PAP system, and air will flow out of the case through that hole until the pressure inside is equal to the atmospheric pressure outside the case. open a hole in the case of a NAP system, and air will flow into the case through that hole - again - until the pressure inside is equal to the atmospheric pressure outside the case. so leaving the holes open in his case prevents the OP from achieving either a positive or a negative air pressure setup.

that being said, i agree with you on your other point - the OP should cover the holes and see what happens...

ideally, the experiment should go something like this:
1) cover the holes, either with plates that do a fairly decent job of sealing them off, or with additional 120mm fans (since that's what those holes were designed for in the first place).
2) play around with several different fan configurations using 2, 3, and 4-fan configurations.
3) either one of the PAP scenarios, one of the NAP scenarios, or one of the unpressurized scenarios will hopefully win out for best airflow and lowest temps. or perhaps you might find that 2 or 3 different configurations all hit the same low temperature that the other configurations couldn't hit.

this may seem like overkill considering you're not having problems with overheating...but you did mention wanting to get the best out of what you've got, and this is the only way you're going to get there.

 

[janas19]

Ok, you are right - I suppose that's why I added "if anything."

 

[pauldun170]

In the past I've blocked off various vents and unused holes.
Negligible effect on temps but it really depends on the case and components.

 

[llee]

The more holes you have, the less efficient your cooling is. Block em!

 

[CupCak3]

No, positive air pressure means essentially more air is entering than exiting.

If you have "holes" it will create negative air pressure, if anything.

Some people in this thread look to need a fluid dynamic lesson but its already been a long day...

I block off all my unused ports. I only buy cases anymore with dust filtration so I want to ensure any air entering my case gets filtered first.

 

[janas19]

Some people in this thread look to need a fluid dynamic lesson but its already been a long day...

I block off all my unused ports. I only buy cases anymore with dust filtration so I want to ensure any air entering my case gets filtered first.

Some people need to read more carefully before posting - note the operative phrase "IF ANYTHING."

 

[fluffmonster]

Throw some masking tape over holes and test. Easy. I often sew filter material onto airways that are left open (my cases are usually configured net-negative airflow).

 

[Charlie98]

I actually have more or less the same question... my HAF922 has half the side case open (no fans installed.) Because the air flow on this new case is so much better than my old Dell (I have 4 fans, 2 pull, 2 push, plus 2 HSF) I've found it's getting far dustier inside (being very near my paper shredder doesn't help... AT ALL.) I'm going to have to find a filter solution pretty soon, having the open side cover doesn't help, either.

Throw some masking tape over holes and test. Easy.

...and that's not a bad idea.

 

[Binky]

A good case will be designed to have decent airflow over the key components. The air path is by design, and large fan holes with no fans could be changing the air path in the case. One potential result is airflow near the (original) intakes is very low, leading to things like high HD temps.

Testing this is very easy. Let it run for a while and check temps at key places/components. Then cover the holes and see if it changes. It may not matter, or it may matter a lot.

 

[gramboh]

Can computer case fans really generate enough airflow to change the air pressure inside a computer case versus ambient? I doubt it. But it does make sense to try to restrict air intake to filtered fans in terms of reducing dust, which is my goal with my next build (damn cat hair). I think that is a question of airflow and turbulence more than pressure.

 

[scannall]

Can computer case fans really generate enough airflow to change the air pressure inside a computer case versus ambient? I doubt it. But it does make sense to try to restrict air intake to filtered fans in terms of reducing dust, which is my goal with my next build (damn cat hair). I think that is a question of airflow and turbulence more than pressure.

It really takes very little differential in pressure to be positive pressure, and reduce your dust levels. Just the smallest amount of positive pressure makes a large difference.

 

[Binky]

It really takes very little differential in pressure to be positive pressure, and reduce your dust levels. Just the smallest amount of positive pressure makes a large difference.

So does a vacuum cleaner!

 

[Sunny129]

Can computer case fans really generate enough airflow to change the air pressure inside a computer case versus ambient? I doubt it.

you can doubt it all you want, but the proof is in the pudding. computer cases are not vacuum chambers, nor are they air-tight by any stretch of the imagination. but the bottom line is that, so long as the rate of air in is not equal to the rate of air out, and there aren't any gaping holes in the the case, then there will be a pressure differential.