[Dust]

the idea behind positive pressure is that you have so much air being circulated through the case that dust essentially has no place to land & filters itself out

 

[wompwomp]

ahhh yes that is true. Looks like I'm adding 14 more intake fans in my case then. rofl.

 

[SpeedNuggeT]

you sort of need positive pressure to maintain good airflow in a gaming PC.

Just use dust filters on all the intakes to minimize it.

and no, you don't need 14 intakes on your PC.

Just stick to the traditional PC airflow of intake at the front/side and outtake on the top/back

 

[Tom Thumb]

Quote:

Originally Posted by wompwomp;14172167
I read somewhere that positive pressure will reduce the amount of dust in your case but I always thought it was the other way around since it's bringing in more air. Is this true?

Only if your intakes are filtered!

Negative pressure will suck unfiltered air in through all the openings in your case. With positive pressure, the only air coming in will be filtered, and the excess air will be blowing out of all the openings in your case! This means less dust!! The only draw back, is that you should have better temps with negative pressure than positive. Until your case and heat-sink fill up with dust that is! LOL

 

[Epitope]

Quote:

Originally Posted by Dust;14172195
the idea behind positive pressure is that you have so much air being circulated through the case that dust essentially has no place to land & filters itself out

No...

the idea is that with positive pressure AND AIR FILTERS 100% of the air inside the case has passed through a filter and is dust free. With negative pressure the air is sucking in through every crack in the case and it is impossible to keep the case dust free even with filters.

My FT02 is a positive pressure case with filters on the intakes. It is dust free about 8 months after assembly. It looks almost as clean as the day I built it and I have done minimal cleaning. I admit to doing a couple quick squirts of canned air but probably less than 2 minutes worth of cleaning in the past 8 months.

 

[wompwomp]

But even with dust filters, it doesn't filter 100% of the dust..

I do believe in the user "Dust" statement a lot though. If you have a good amount of air flowing through your case, it will not allow any dust to settle or land. Instead the dust will have no choice but to be exhausted by the exhaust fans.

 

[Dust]

Quote:

Originally Posted by wompwomp;14172600
But even with dust filters, it doesn't filter 100% of the dust..

I do believe in the user "Dust" statement a lot though. If you have a good amount of air flowing through your case, it will not allow any dust to settle or land. Instead the dust will have no choice but to be exhausted by the exhaust fans.

positive pressure works - but it works better with filters.

 

[Jagged_Steel]

Quote:

Originally Posted by wompwomp;14172167
I read somewhere that positive pressure will reduce the amount of dust in your case but I always thought it was the other way around since it's bringing in more air. Is this true?

Really? Looks like you "read somewhere" about this in the thread you were trolling a couple of days ago on this exact same subject. I guess you get some thrill out of being a PITA and clogging up the board with garbage on subjects that you have no knowledge of.
Quote:

Originally Posted by wompwomp;14130372
Go for ultimate positive pressure! 6 intakes no 0 exhaust fans! Remove all of your dust filters as well for maximum cooling! beyahhh!!!!

http://www.overclock.net/air-cooling/1059798-5-intake-1-exhaust-enough-6.html

Quote:

Originally Posted by Jagged_Steel;14124304
The comment about Positive Pressure making your rig look like "the inside of a bagless vacuum cleaner" is 180 degrees off.

My experience says the opposite of this statement. As another poster noted: In a Negative Pressure system there will be air coming in through every available hole in the case- meaning it will not be filtered. In addition to this is the issue of pressure drop relating to the density of the air in the case compared to outside. I tried a negative pressure case mod to my last Compaq POS rig and it did indeed behave like a bagless vacuum and did little to cool down the old beast. Turning the majority of the fans to blow in and making sure they drew air in through a filter dropped my case temps like a stone and it was clean as a whistle inside- even after months of grinding away. A bagless vacuum cleaner utilizes a DROP in air pressure (negative pressure) to make the particulates fall out of the airstream. Look at a Dyson- those venturies you see compress the incoming dirty air and then rapidly decompress it- this decompression causes the particulates to fall out. Less pressure = less velocity and less fluid tension- which is what holds particulates in suspension in the first place. So having all fans blow out, which creates a pressure drop to air when it enters your case, will indeed make more particulates fall out of the air and stay in your case.

Something that I did not see mentioned anywhere - including the very nice breakdown of cooling system types by N-Sanity, is the basic physics involved in heat transfer. IMO the conclusions he presented are correct, but nowhere did I see mentioned the fact that denser air has a larger mass to soak up heat with. All computer cooling schemes rely on heat transfer rather than heat Radiation (not including computers in space which rely solely on radiation). Heat TRANSFER requires mass to transfer said heat to. No mass = no heat transfer. This is why Thermos bottles have a (near) vacuum for insulation. The only heat that escapes from the inner vessel in a Thermos is through radiation. This is also why liquid (water- mineral oil- etc) cooling is so effective compared to air cooling - you are providing a large amount of MASS for the heat in your machine to TRANSFER to. The air must of course exit the case after soaking up heat, but having more fans blow in than out will result in a Positive air pressure and better cooling than a reduced air pressure system.

 

[Tunagoblin]

It is actually more of how dusty the room is...
If your room is dusty and dirty or you place your comp on the ground, w/e you do, your comp gets dusty...
But at the same time there is no dust free environment in normal residence anyway...
Unless you place your comp in dust free Air conditioned container...or have dedicated machine room....
Just clean periodically solves the problem, though.

 

[PARTON]

Remedy:

Once per week,
turn of computer(s)
vacuum and sweep
then wipe counter and table tops.

My wife is very good about this and my computer has little dust.
When I had no wife, the inside of my case was very dusty.

 

[Dust]

Quote:

Originally Posted by PARTON My wife is very good about this and my computer has little dust. When I had no wife, the inside of my case was very dusty.

 

[wompwomp]

Quote:

Originally Posted by Jagged_Steel Really? Looks like you "read somewhere" about this in the thread you were trolling a couple of days ago on this exact same subject. I guess you get some thrill out of being a PITA and clogging up the board with garbage on subjects that you have no knowledge of. http://www.overclock.net/air-cooling...-enough-6.html

Trolling? Rofl. It's called joking.. Check like 3-4 posts below that one. Do yourself a favor a get a sense of humor as well as a life brah.

 

[Jagged_Steel]

Quote:

Originally Posted by wompwomp;14180734
Trolling? Rofl. It's called joking.. Check like 3-4 posts below that one. Do yourself a favor a get a sense of humor as well as a life brah.

A joke has a punchline and it is supposed to make OTHER people laugh. I fully understand that you are amused by mindlessly stirring things up with no goal other than "amusing" yourself - otherwise known as TROLLING. Have fun sitting around laughing at your own "jokes" there dude.

BTW, my sense of humor is just fine, I am just not "easily amused" like you are by wasting other peoples time and generally being a PITA with your "jokes"....

 

[Just a nickname]

Beside dust stuff, positive pressure is a good way to avoid hot air pockets.
Just to mention

 

[wompwomp]

Quote:

Originally Posted by Jagged_Steel A joke has a punchline and it is supposed to make OTHER people laugh. I fully understand that you are amused by mindlessly stirring things up with no goal other than "amusing" yourself - otherwise known as TROLLING. Have fun sitting around laughing at your own "jokes" there dude. BTW, my sense of humor is just fine, I am just not "easily amused" like you are by wasting other peoples time and generally being a PITA with your "jokes"....

How do you know others didn't laugh? Because you didn't? Someone quoted my post asking if the BEYAH was from dave chapelle therefor someone was obviously interested.

And wasting other people time? Your the only person that seems to have a problem with my post/threads. Oh yeah I forgot, there's a simple solution for that, don't read nor respond to any of my post and **** of my thread. kthx bu bye.

 

[Jagged_Steel]

Poor Troll. Rather sad to hear them scream and see them thrash around when you pull them out from under their bridge into the sunlight.

 

[SirWaWa]

when I switched to positive pressure dust accumulation dropped like 90%

 

[wompwomp]

Quote:

Originally Posted by Jagged_Steel Poor Troll. Rather sad to hear them scream and see them thrash around when you pull them out from under their bridge into the sunlight.

Yes, that's exactly it.

 

[donkrx]

Quote:

Originally Posted by Jagged_Steel This is also why liquid (water- mineral oil- etc) cooling is so effective compared to air cooling - you are providing a large amount of MASS for the heat in your machine to TRANSFER to.

Well... more mass helps, but that's overlooking a lot of things. First off water is more dense so we need a lot less volume to accomplish the same thing, if all other material properties of water and air were the same.

Anyway, more importantly than that are the thermal properties: water has a MUCH higher specific heat and thermal conductivity compared to air. This means that water can still displace the heat better than air without having to worry about keep the water super cold .... and thus it doesn't take loads of power to implement water cooling (thus practical/possible). When you get out of a shower, even if it was a hot shower, you will quickly lose heat to the droplets on your body and feel cold.

Considering what you said about mass - specific heat means, gram for gram, water is still superior - so mass isn't really the best metric to use, though you do have a point that heat needs something to transfer into.

Radiation is still a method of heat transfer. They are not different as you implied. Conduction, convection and radiation ... all methods of heat transfer, so I'm really not sure what you meant. Conduction is through solid materials, convection through fluids (fluid=liquid or gas), radiation through electromagnetic waves.

Quote:

Originally Posted by Jagged_Steel The air must of course exit the case after soaking up heat, but having more fans blow in than out will result in a Positive air pressure and better cooling than a reduced air pressure system.

I agree, more fans blowing in is better than more fans blowing out. Keeps your case filled with cooler air. But pressure really doesn't matter except for dust, which admittedly is really very bad (if you do the calculations) for heatsinks.

To keep your heatsink working to its best you need to keep your case ambient temp down (via your house AC and fan arrangements) and the airspeed over your heatsink up. My case has a 200mm exhaust fan right above the CPU, and the typical top-rear fan as a 2nd exhaust. This gets rid of hot air immediately while the cool air is refreshed on the bottom. You don't want your fans at the top of your case to be blowing in... heat rises... but i think we all know that one.

=====

EDIT: btw, I've never used them, but I would expect dust filters to reduce the CFM of your fans, which is not good either. Could just clean the case out every once in awhile.