Top fan = vacuum?

[andy5174]

There are a lot of cases with top fan these days. Does it make the case dusty quickly and easily? It is the major concern for holding me back from purchasing those cases.

 

[imrul]

depends if it's intake or output

 

[andy5174]

I mean the output ones. For example, the one come with Antec 1200 or CM HAF 932.

 

[buzznut]

It shouldn't be. I have an Antec 900 and it has great airflow and I typically blow it out with canned air every one to two months.

The idea of the blowhole is that heat rises so install an exhaust fan in the top so heat won't be trapped inside the case. It works.

I find a case located down on the floor or close to it will gather dust more quickly than one on the desk or file cabinet. Especially if you have pets like we do.

 

[buzznut]

Also if you're that concerned you could always install some filters.

 

[andy5174]

Also if you're that concerned you could always install some filters.

I did try to search the filters. However, the largest one I found is for 90mm fan.

 

[andy5174]

canned air

What is that?

 

[croc]

I did try to search the filters. However, the largest one I found is for 90mm fan.

Panty hose, mate... Make your own filters. HEPA 2 rated, good stuff. (best wait until your partner, mum, or significant other blows out a foot or somesuch...)

 

[andy5174]

Panty hose, mate... Make your own filters. HEPA 2 rated, good stuff. (best wait until your partner, mum, or significant other blows out a foot or somesuch...)

ROFL! I need it immediately. Perhaps I should make it blows out a foot right away with some mysterious magic.

 

[croc]

ROFL! I need it immediately. Perhaps I should make it blows out a foot right away with some mysterious magic.

OK, buy whomever a new pair, and make a trade... (Trying to be 'magical' around females is a sure formula for 'issues'.) Or buy a pair, and let her see you with a pair of scissors threatening to cut them up... I can hear it now...

Whichever you play it, you get enough filter material for several builds.

 

[andy5174]

It was a joke. btw, why would you buy a new pantie hose and trade it for a smelly 2nd hand one? There will be a great chance that you will get slapped if you do so, as she might think that you are a HENTAI.

Warning to everyone(male ONLY): Only do this if the "she" is your most close mate. Otherwise, get a new one or do the magic secretly. Nah, never do the latter!

 

[tmike]

Remember too that with or without a topside fan, dust can be greatly reduced by adding additional intake fans to maintain positive case pressure.

 

[andy5174]

Remember too that with or without a topside fan, dust can be greatly reduced by adding additional intake fans to maintain positive case pressure.

True. The higher pressure inside will keep air from flowing into the case and more heat dissipated at the same time. You must be good in Physics.

 

[JackNaylorPE]

There are a lot of cases with top fan these days. Does it make the case dusty quickly and easily? It is the major concern for holding me back from purchasing those cases.

No, it's better for air flow as fan isn't fighting nature. It's better if you obey gravity (after all it's "the law") and hot air is lighter than cooler air so hot air rises. You don't want a filter on this fan, only filters on intake fans which many cases provide.

 

[andy5174]

No, it's better for air flow as fan isn't fighting nature. It's better if you obey gravity (after all it's "the law") and hot air is lighter than cooler air so hot air rises. You don't want a filter on this fan, only filters on intake fans which many cases provide.

In the theory, it is. Is it true in the real world as well? What's your case btw?

 

[croc]

No, it's better for air flow as fan isn't fighting nature. It's better if you obey gravity (after all it's "the law") and hot air is lighter than cooler air so hot air rises. You don't want a filter on this fan, only filters on intake fans which many cases provide.

Many data center engineers would choose to politely disagree. PPV seems to be the way to go, with about 3 to 5 PSI differential generally being agreed on. All air intakes to be well filtered, but no filters on the exhaust. On this point we'd agree. BUT... By design, datacenters use top mounted intakes, air-flow floors, and bottom mounted exhaust ports. So go figure.

 

[andy5174]

Many data center engineers would choose to politely disagree. PPV seems to be the way to go, with about 3 to 5 PSI differential generally being agreed on. All air intakes to be well filtered, but no filters on the exhaust. On this point we'd agree. BUT... By design, datacenters use top mounted intakes, air-flow floors, and bottom mounted exhaust ports. So go figure.

so you mean that the top fan can make the case dusty easily?

 

[hypocrisyforever]

Hmm....I use a cooler master stacker with 7, 120mm fans and because of the "filters" they provide with it, it is always very very clean. I open it up to dust it out at least once every 6 months as a matter of maintenance, but it is always super clean. Only 2 of my fans do not have filters, both exhaust fans: the one at the top, and one at the back (where my zalman heat sink blows air to the exhaust fan). So really the only place dust could feasibly come in easily is the top and like I said, it doesn't happen. I certainly wouldn't let a top mounted exhaust fan hold you back from buying a case you like. Also, clean your computer occasionally ;-).

 

[pilode]

There are a lot of cases with top fan these days. Does it make the case dusty quickly and easily? It is the major concern for holding me back from purchasing those cases.

After 25 years of having PC boxes laying on the floor, I would say the problem is not so much dust as lint (but lint is not "that" light) and cat's hair (which IS light and seem to float about in mid-air forever, and so often manages to get sucked in). But the very worst is cigarette smoke: it propagates like... well... smoke, then leaves a sticky deposit, very hard to get rid of.

I have both Antec's P180 et P182, which come notably with a top exhaust fan (rear) and pre-installed filters on the intakes (two, front). Filters work great for me: I will no more have a case without intake filters. I keep both cases on the floor---off on 1 or 2 inch risers, though, to spare the filters of the worst of the floor lint. I run the front fans at lowest speed (1200 rpm for the 120mm TriCool) and that "seems" to be enough to overcome intake restrictions and establish and organize air flow inside the case---and not add much to the ambient sound level. Don't have a cat anymore but I still smoke---heavily---and I can SEE the top fan (120mm TriCool, running at 1200 rpm mostly) repelling the cigarette smoke. I can't detect cigarette smoke deposits inside the case---nor lint or dust, but I do get to see (monthly) what the filters trap!

So I'd say: don't hold back on account of dust. But if your setup NEEDS your top fan to run at high speed (OC?), then I concede it might be noisier that back panel fans. (Myself, I'll be experimenting with different front and top fans---and maybe a fan controller---when I try to OC my P182, in a couple of months.)

Regards.

 

[JohnnyLucky]

The answer to your original question is it depends. The fans themselves do not make the case dusty. It is the air being pulled into a pc case that contains particulate. The dust has already entered the pc case before it reaches an exhaust fan. A lot of the newer cases are very well ventilated. By that I mean they have a lot of perforated mesh and openings to allow air to enter the case. The idea is to improve airflow and cooling. Unfortunately they also allow dust to enter the case, though not as much as case fans.

The typical solution is to either purchase a case with fan air filters, purchase air filters from online vendors, or make them yourself. The downside is that the filters restrict airflow and cooling capacity. People typically deal with the reduced airflow and cooling by installing high volume, high rpm case fans.

 

[JackNaylorPE]

In the theory, it is. Is it true in the real world as well? What's your case btw?

Yup, in real world gravity still works, I haven't fallen off the planet yet.

But, yes, using an infrared thermometer if I can get air outta the top of the case, things run smaller. I have about 20 cases between here and office, latest build is a 1200.

 

[sminlal]

By design, datacenters use top mounted intakes, air-flow floors, and bottom mounted exhaust ports. So go figure.

That's certainly not true of the IBM, DEC, Compaq and HP cabinetry I've worked with. That equipment is designed for use in a raised-floor computer room where air conditioned air is fed under the floor and then rises through openings up into the cabinets with exhaust fans at or near the top.

 

[tmike]

That's certainly not true of the IBM, DEC, Compaq and HP cabinetry I've worked with. That equipment is designed for use in a raised-floor computer room where air conditioned air is fed under the floor and then rises through openings up into the cabinets with exhaust fans at or near the top.

Agreed. I run those same systems, with the addition of DG (RIP) which I mention only out of respect for The One True Operating System (Unix, by which I do not mean Linsux) and have always run them in the configuration described even when some cabinets required customized air ducting to conform.

Of course, the subfloor in production environments is not as dusty as mine at home - so naturally my primary system case has two intake fans at floor level (*eyeroll*) for one of the drive cages. Thank goodness it has a built-in reusable filter.

 

[buzznut]

So I would agree with the airflow difference being either a positive pressure or negative pressure.
Ideally you would want either more air being pushed into the case or more air being pushed out (like a 250MM exhaust fan on top) The reason for this is that if you have equal amounts of CFM's on both sides of the case, the pressure inside will be zero (or perhaps 1 atm would be more accurate) which creates "dead zones" or pockets of heat build up surrounding certain components.

not good.

As for the idea that dust will "fall in" the machine with a top mounted fan, I suppose a little bit will when the machine is off. However in my experience my intake fans are always dusty, whereas the top fan hardly ever collects any.

Some places sell compressed air for about 5-6 bucks, (office supply stores) thats a little high. I usually get a six pack at sams for 18, so about $3 a can. It lasts me about 8-10 months, but I work on a lot of pcs. Saved my wife's keyboard and mouse after a nasty full-cup-of-coffee spill the other day. I find them absolutely necessary.

 

[andy5174]

Some places sell compressed air for about 5-6 bucks, (office supply stores) thats a little high. I usually get a six pack at sams for 18, so about $3 a can. It lasts me about 8-10 months, but I work on a lot of pcs. Saved my wife's keyboard and mouse after a nasty full-cup-of-coffee spill the other day. I find them absolutely necessary.

What exactly is the compressed/canned air? Is it a kind of cleaner? How does it work? Will I be able to get it at local computer retailer shop?