Tested: Positive vs. Negative Air Pressure

[tigerwoods]

I always thought positive air pressure is the right way.

 

[wwenze]

You aren't wrong if your situation calls for positive pressure. Because I have no idea what that experiment is trying to prove.

12cm fan PSUs and Intel BTX specification would want to have a word with the author. Plus what about laptops with a bottom intake hole directly at the CPU fan, does that count as positive or negative air pressure?

Once you figure out how to treat the last scenario and understand fan curves, you'll realize the positive vs negative experiment makes as much sense as the statement "...and also an array of (3300rpm) fans more effective than one big (silent) fan..."

 

[hlots123]

i prefer the air going front to all the way back, and running the rear fan faster so altho +ve but aiming for "neutral" pp lol...

 

[Crooni]

the video doesn't do anything. the pc seems to be build for negative (3 exhaust vs 2 intake), when what you really want is to increase intake (more fans larger fans higher rpm) without reducing exhaust like in their positive "test".

positive/negative is for dust. ppl keep it positive so that that most of the air going in will be forced through filters. if it's negative then more air/dust will enter through any hole there is.

the way they showed positive was by making exhaust slower, which of course would impede airflow.

 

[Entry Level PC]

heng i use open air casing and my duaki leaf blower for cleaning.

 

[ragnarok95]

Like I said, positive or negative you need to try it yourself, don't just blindly follow what people say and when the result doesn't go your way then you start to question the equation.

Simply some here are just too lazy to conduct tests for themselves.

 

[enenyi]

I find that for our climate, positive vs negative vs neutral air pressure doesnt matter as much since no matter how many dust filters u have, u still cant stop dust from settling in when the PC is powered off (via areas like pcie brackets etc). I feel whats more important is whether generated heat can escape the PC or not, coz more likely trapped heat in PC will do more harm to the components than trapped dust in PC. Of which means u prob need good airflow for heat generated by CPU and/or GPU to escape the PC.

 

[wacko]

when i have the time, i'll show what it is like inside my casing after 1 year of running 24/7, with positive air pressure, and all intakes dust filter controlled. this is roughly equivalent to 3 years of running at 4 hours per day.

 

[gld998]

when i have the time, i'll show what it is like inside my casing after 1 year of running 24/7, with positive air pressure, and all intakes dust filter controlled. this is roughly equivalent to 3 years of running at 4 hours per day.

Same here, mine is possitive air flow. 2x front, 1xside and 1xback suck in air then 1x fan at top suck out. How to suck out air if the is no air to suck out.

Sent from Samsung SM-T719Y using GAGT

 

[ragnarok95]

Front 140mm 1200rpm with filter at hdds. Middle 120mm 1200rpm at gpu. Back 120mm 1100rpm exhaust.

Side vent open with no filter.

 

[idjekyll]

Just quick note. Those using reference cards has to factor is how much are it exhausts to contribute to the negative/positive issue. I have 3 intake and 1 exhaust so I thought that would create a positive environment but the dust filter that has no fans would collect a buttload of dust Everytime I do my case cleaning. Correct me if I'm wrong but that's a sign of negative environment right?

 

[gld998]

Just quick note. Those using reference cards has to factor is how much are it exhausts to contribute to the negative/positive issue. I have 3 intake and 1 exhaust so I thought that would create a positive environment but the dust filter that has no fans would collect a buttload of dust Everytime I do my case cleaning. Correct me if I'm wrong but that's a sign of negative environment right?

I clean all my 9 machines every 6months

Sent from Samsung SM-T719Y using GAGT

 

[commach]

Just quick note. Those using reference cards has to factor is how much are it exhausts to contribute to the negative/positive issue. I have 3 intake and 1 exhaust so I thought that would create a positive environment but the dust filter that has no fans would collect a buttload of dust Everytime I do my case cleaning. Correct me if I'm wrong but that's a sign of negative environment right?

Technically right, partial negative due to not all air intake are covering the casing. Actually doesn't really matter much as long as temperature within the casing is at moderate level.

Your case is like blowing a 300mm diameter by 5 meters long blind end air tube with your mouth alone. How many blows your need to fill this tube with air just by using your, I guess you probably fainted before the tube filled up. If you bow this tube some 30cm away from the opening, you probable need less than 5 blows to filled up the tube with the assist of the surrounding air.

 

[Koenig168]

I do front and bottom in, back and top out. This keeps air moving in one direction.

 

[royfrosty]

Chim sia.

All i did is to balance the airflow of my Lian Li o11 case.

One thing i noticed, not all casing are the same in pulling air into the case.

Also to account things like how the fans are mounted. Whether is it with radiator or not with radiator.

For my case, hardware labs radiator has a very high density fins. I cant use normal airflow fans to push those air through it. Although, yes i can do that but not very effective especially when overclocked.

I managed to balance the airflow. I remembered most of the reviewers mentioned it is best if you can balance the airflow.

But its not that easy to achieve. Fans mounted on radiators are resistive. Fan mount with nothing obstructed brings air in easily.

I did 3 fans at the front with moderate 900rpm range. My rads i managed to control it at 1400rpm.

My rear has no fans, and a quick test using incense stick, the smoke didnt travel back in from the rear. Neither does it blow out.

Took me 3 days to figure out the rpm at what kind of situation etc. Remember not all case brings in airflow the same way. Some draws in air differently.

Also there are some factors you may want to consider. Positive airflow iirc your dust build up can be bad. Worse if the pc is on the floor. Negative airflow on the other hand dust build up is minimal.

 

[haze_1986]

positive = less dust, not so streamline flow. (assuming you have dust filters in intakes)
negative = cooler, proven by CFD simulations. Air will enter from all the holes in your case, which result in dust.

 

[bloodlovers]

used to run negative pressure because it was 2-3 degrees cooler. but after just a week, a very thin layer of dust can be seen on my gpu backplate due to the gpu being directly under the vent holes. my case is placed about 160 cm above ground and even then, dust built up too fast for me to justify the marginally cooler temps.

Sent from Samsung SM-N920I using GAGT

 

[poring24]

positive less dust in your case

 

[evildoctor]

Anybody tried Valore Air Blower before?