A high number of intake fans will create lots of air pressure that helps the hot air of the gpu being exhausted trough the case vents ( showing in the picture below ) not occupied by case fans. If you want to go that route, you should also be sure that the heat sink on your processor isn't being artificially handicapped. The NZXT H500 and 510 series cases are specifically designed to be negative pressure. Negative air pressure: More fans are blowing air out of the case than drawing air in, causing a slight vacuum effect. Acer Nitro XV272U KVbmiiprzx Monitor Review: Your Money’s Worth, AMD Smashes Records Again, Data Center and Semi-Custom Revenue up 286%, Consumer Up 46%, Get $140 off This Acer Predator 1440p Gaming Monitor, The Linux Foundation Has a Few Demands for Banned University. I have 2 120mm stock fans as exhausts, but they push probably a forth of the air combined as 1 140mm Noctua intake fan. Air flow: positive or negative pressure As a first step, it is crucial to decide which type of pressure system we want to achieve, as this determines the type of fans to purchase, as well as their position inside the case. The higher pressure in the case compared to the lower pressure on the outside means that the air you do not pump out will travel from the inside of the case to the outside via the gaps on the case. That many intake fans will most likely contribute to positive air pressure within the case, though (See the advanced section at the end of this guide for details on case air pressure). A self-professed tech hipster that loves computers and music. Positive pressure – The case fans push more air into the case than then pull out, so there is more air pressure inside of the case. Your negative pressure graphic is not likely as you would never exhaust out the front. Please refresh the page and try again. Every fan features a cubic feet per minute (CFM) rating, which measures of the volume of air it moves in a minute. I have a NZXT H500 case, it has 1exhaust on the back and 1 on the top aswell and i have a NZXT kraken x62 for cpu liquid cooling and the radiator is mounted at the front with 2 intake fans. I had an expensive gaming computer built and I noticed they installed the cpu liquid cooler radiator w/ (2) 120mm fans over top of the (3) 120mm case fans at the front panel. The shroud design produces temperatures from 10-30 C above the case exhaust designs. In most situations, air enters through filters near the floor, and then is sucked out through filters in the room ceiling. Otherwise, all the airflow in the world won’t help much to cool down your components. Negative pressure – More air is being pulled out of the case than being pushed in, creating a vacuum. Otherwise, you may end up with a toaster oven of a computer. If the intake CFM is greater, then you have positive pressure. To reduce dust in the case, ensure that the air going into the case first passes through a filter. Just be mindful of the noise levels as fans can generate quite a buzz. who uses gloves :P I use my finger :) I have been doing it before there was even aftermarket paste :P. On page 5 the second picture the top case fan points down yet hot air comes up. We even wrap up with a recipe you can use if you fail to cool your PC properly. This goes against logic until you account for the resistance of the filtered air and the air gaps. The greater the CFM, the more air a fan moves. How do I measure pressure inside computer case Answered I've setup a home file server and would like to be able to maintain positive pressure in the case to keep dirt out (two dogs in the house). So, I'm running high positive pressure to force all the air coming into the case to go through a dust filter. never knew i could get 7v by crossing the 12v and 5v lines like that (and wouldn't have dared try if i'd even thought of it anyway), glad to know there's another option there! I'm not a professional when it comes to this solution, nor do i have eyes of a hawk to know if i do it right all the time, the temps seem to be right. In simple terms, a computer case can either have: To determine pressure, total the CFM of all the intake fans and CFM of all the exhaust fans. Get instant access to breaking news, in-depth reviews and helpful tips. Optimal air pressure with a computer case is one of the most discussed and debated topics in computer cooling. We wanted to ensure positive pressure in the system. Conversely, when the airflow is greater for exhaust than it is for intake, a negative pressure is created. Future US, Inc. 11 West 42nd Street, 15th Floor, In hindsight, using another method to represent air pressure would’ve been better. More case fans means higher total CFM and more air being moved through your computer. Difficult to attain unless you leave the case open. PC cooling: there’s a right way and a wrong way. It works pretty well stock. This causes air to be sucked in through gaps in your computer case, which can pull in dust, dirt, and hair. Image courtesy of extremetech. Just be sure to actually clean the filters once in a blue moon. to 0.2 in water column (H20). Granted all it really told me is that I was doing it right all along, but it did give me some useful bits of information that I didn't know before. I wish you guys did a temp difference on how the paste was spread in a lot different ways to give me a point of view of if there is any difference in temps, obviously the one where you can see the writing more then likely is not effective. By leaving filters dirty or covered in dust, you reduce airflow and cooling power. Yep, air pressure differences in a case make very little difference to fan output or air density. Helpful even for myself (who has been building PCs for years). On the off chance that the case can’t stack two 120 mm fans in advance, chances are a single 200 mm fan will be utilized all things considered. That is why all the perforated side plates and back plates are that way and the fans are mounted to be exhaust only. It creates positive air pressure inside the room and prevents the air from the ambient environment from entering the room. Uses an iPhone ironically. OPEN THIS DESCRIPTION FOR COUPONS AND DISCOUNTS!Ever wonder what all that talk about caseflow and air pressure means? The case I have is the NZXT Lexa Blackline. We did take some time to air tighten many of those air gaps, but a couple of significant ones remain. This means I have positive pressure happening in my case. Question here, how can you find out the cfm rating of the stock fans that come with a computer case? However, its pressure is relatively low, so its usefulness lies in keeping a directional flow as opposed to in keeping up negative or positive air flows. Neutral would be when intake and exhaust CFM are equal. Whereas if we achieve negative pressure (more air exiting the case than entering) then air would be drawn in through those gaps. There was only (1) 120mm exhaust fan mounted at the rear panel. You should also heed the placement of the fans. To create positive or neutral pressure the total CFM sum of the intake fans must be higher or equal to the total CFM sum of air extracted from the case. The same costs and durability concerns mentioned above are at play here as well, but this is a case … If you have 3 intakes and 2 exhaust you have positive pressure, and will not accumulate dust as fast. Depending on your case, positive air pressure might have an edge in cooling for the reasons mentioned by JackNaylorPE. Should I add additional fans at the top of my case to help with proper air flow? Generally this is achieved by filtering air out of the room. Different flow affects dust build up just as much as the case and house itself. Imo this is hard to measure just by calculation because most of the cases would provide some restriction to the front intake due to the dust filters and stuff on the front panel which makes front fans less efficient – while at least the rear fan has no restriction since there are no filters on the back. i've sometimes moved a fan's molex wires from 12v to 5v for silence's sake, but sometime it was too much. By changing the direction a fan is mounted, it can act as either an intake or exhaust. But, no matter who you ask, someone is bound to tell you something different. Great article as always, cheers! Generally, you want the case fans in front of the case drawing in air while the fans at the rear blow air out. I read years ago that thinner the layer of thermal paste, the better. Positive air pressure means that you have more air being blown into the case than out. What is positive air pressure? In simple terms, a computer case can either have: Positive pressure – The case fans push more air into the case than then pull out, so there is more air pressure inside of the case. After discussing the theory of PC cooling, in Part One, we now move on to technology and implementation, discussing case fans, CPU coolers, and thermal grease. By bringing in outside air in a controlled manner, the ERV keeps the home at a positive pressure, preventing the infiltration of outside air through the walls, floors, etc. I've been doing the whole spread the paste evenly flat onto the CPU/Cooler for almost 8 years now. This is why the argument of positive vs negative pressure is important. I would have liked to seen silverstone's air penetrater fans in here. your first picture is wrong, fan intake is the open side on 99% of fans. You can’t really control airflow at these points unless you want to put caulking or sealant in your case. gloves? Photo by Jeff Kubina, taken from Flickr Creative Commons, An IT asset management plan for remote workers using company laptops is more critical now…, Do you need a rundown of what you can do to help your staff during…, Working from home may have its benefits (who needs pants in a Zoom meeting, anyway? This way, the air that enters your case goes through a filter first. Thank you for signing up to Tom's Hardware. Just be sure to avoid those tacky LED-equipped case fans in the office. It’s where you have more air being sucked into the case than is being pushed out by the fans. Visit our corporate site. Side-mounted fans should be used for intake, though they often don’t have air filters. You will receive a verification email shortly. Lots of youtube videos about people monkeying with them to try to get better cooling / higher flow with mostly poor results as even higher flows don’t actually do much to temps (esp GPU temps as the stock config negative pressure draws cool outside air right across the GPU’s own fans). To properly air cool your computer, you need have enough case fans to push or pull air into and out of the case. There needs to be rhyme or reason to the setup or else it becomes something wholly inefficient. While having some positive internal air pressure inside your case is a good thing, it is not the best if it’s to the extreme. Keep in mind that you cannot achieve positive pressure in a case with meshed surfaces or lots of openings. In theory, if you are going with negative air pressure, you would consequently have to add dust filters to every opening (since air/dust will be sucked in those openings). This might sound contradictory at first, but if you think through it, it will make sense. Equal air pressure: The same amount of fans are blowing air in and out, creating approximately the same air pressure as the surrounding room. All the other holes in the case have air blowing out of the case, due to the positive pressure. To prevent dust issues, you can custom fabricate your own filters. Filtered incoming air and positive/neutral air pressure equals much cleaner case interiors. ),…, PC Cooling: How to Set up Computer Case Fans, 6 Reasons Your PC is Slow and How to Fix It, 5 Ways to Stream from PC to TV or Digital Display, How Digital Technology is Transforming Local Government, The Quiet Office: Turn Down the PC Noise - HardBoiled, Building A PC : 31 PC Building Mistakes to Avoid. Ensuring your computer receives sufficient cooling with PC case fans isn’t rocket science but it can be tricky. If your case is more or less airtight (fan openings excluded), the ratio between intake and exhausted air determines whether positive or negative pressure develops inside. Sean and Norm discuss the effects of negative air pressure compared with positive air pressure in PC cooling, and test different configurations for maximizing airflow through a computer case. If exhaust CFM is greater, then you have negative pressure. In medical settings, these rooms prevent the spread of infectious contaminants and maintain sterile or restricted spaces and are also referred to as Protective Environments (positive pressure rooms) and Airborne Infection Isolation Rooms (AIIR) (negative pressure rooms). By positive pressure, I mean that the air pressure inside the house is higher than outside pressure, which tends to push air from inside to outside. If your case is more or less airtight (fan openings excluded), the ratio between intake and exhausted air determines whether positive or negative pressure develops inside. After discussing the theory of PC cooling, in Part One, we now move on to technology and implementation, discussing case fans, CPU coolers, and thermal grease. These vents can become either exhaust or intake depending on whether the chassis has positive or negative air pressure. Thanks for the feedback. With this in mind, for those serious about clean PC's, you may want to look into the use of positive air pressure in a PC case. New York, Positive v. negative air pressure. This keeps the air inside your home cleaner and less humid, while helping your HVAC system to … So my question is, should i flip the top fan to be an intake and leave the one on the back as an exhaust? Positive air pressure is the opposite. I think that you may have proven my case for GPU cooling being superior as a case exhaust design over the shroud design. Current page: Positive air pressure simply means that more intake air is forced into the chassis than air is being exhausted. If neither of those is the case, the air leaking out through hole that you found must be leaking in elsewhere - it's normal to have negative pressure at the bottom and positive pressure at the top due to stack effect, but ideally this should be minimal if we seal the leaks. Aim for slightly positive pressure, with slightly higher intake CFM than exhaust CFM. Just to see how they stack up against other fans. Computer chassis are typically equipped with many case fans, some are designed for exhaust and others for intake. That left us with 2 fans exhausting the warm air. We break down the fundamentals of air cooling your computer so you can avoid a Chernobyl-like meltdown. Negative air pressure will mean that you are pulling in unfiltered air through every crack and crevice in the system, including through components like floppy drives. If your case has vents at the top, they should be placed as exhaust fans because hot air will rise. Speaking of dust, you want to make sure that your computer remains as dust free as possible. You want as close to a laminar flow as you can get, which just means as smooth and unobstructed as possible. Air travels one way through a fan, in one side and out the other. There was a problem. My case came with 4 fans, 1x 80mm and 3x 120mm but I can’t find any info on the cfm rating of the fans.. Is there any software what I can install to get these ratings as most software just gives you if the fan is working or not and at what rpm.. We even wrap up … Tom's Hardware is part of Future US Inc, an international media group and leading digital publisher. Positive Air Pressure Cleanrooms normally operate in an air pressure range of 0.02 in. Also, flashing multi-color lights shouldn’t be the main feature of your case fans. We're talking about fractions of a percent. To Calculate what you need to setup positive pressure in your computer or electronic unit's case, please follow the information and instructions below. A single intake fan with no exhaust fan is positive pressure. The intake fan(s) have a higher rate of airflow compared with that of the exhaust fan(s). If you want maximum PC performance, which means turning massive amounts of electricity into heat, you should carefully consider the cooling strategy you want to adopt and the best-suited case for it. Case Fans: Should You Worry About Positive Or Negative Pressure? Reversing would be bad as the 2 are so close together they would cancel each other out in a small area and give most of the case NO airflow. Positive pressure simply keeps the dust out of your computer, as long as you have some positive you win. Aside from fans and vents the other major points of ingress include the many small gaps in the chassis and adjoining pieces. Optimal air pressure with a computer case is one of the most discussed and debated topics in computer cooling. In a perfect scenario, you’d have neutral pressure with an enclosed case because no dust would be sucked in. Updated Feb. 2021. When building your computer, be sure to configure your cooling system with the principles outlined above in mind. The room must be properly sealed to maintain the positive air pressure in the room. Sure, you could take the “maximum power” approach of shoving as many fans as possible into and onto the case, but that’s far from ideal. © Air leaking out (or into) either the intake or exhaust ducts from your HRV or ERV will affect the balance of air pressure and will likely produce a negative or positive indoor environment. To avoid making your computer too loud, use fewer or quieter fans. Of course there’s the CPU and GPU coolers as well as the PSU playing into it. Positive pressure configuration is the reverse of the negative pressure setup with two 140mm fans at the front of the case for intake and a single 120mm fan exhausting hot air … Or just make them both exhaust? If that's practical is questionable. Really good article, and a real help. Does this configuration compromise the intake cfm’s? NY 10036. Negative pressure would mean that air is being sucked into your case from all the tiny gaps you can’t control and don’t have filters on, which means less efficient cooling over time. A single exhaust fan with no intake fan is negative pressure. The first image of the fan has been replaced. Originally published Sept. 2015. Positive air pressure means the cleanroom or rooms are "pumped up" with more filtered air then the surrounding space outside the cleanroom(s). All of which are bad for your cooling situation. Which is better within a computer case; positive or negative airflow? This is how air circulates through a computer case. You really could have spent a little more time on this to make it easier to comprehend for the beginners. These fans or filters help to create high air pressure by blowing air into the room. Negative Air Pressure Cleanrooms . In a negative air pressure cleanroom, the air pressure in the room is lower than the pressure outside of the room. If you do add intake fans in front there is limited ventilation for them to bring in much air since the front panel is solid, and it will mess up the negative pressure design unless you upgrade to higher cfm exhaust fans too (and since NZXT is also a fan maker these cases have AER f120 fans instead of generic cheapo fans). The high-speed camera footage doesn't lie! If we attain positive pressure (which means there is more air entering the case than exiting) then air will escape the case via those gaps. Either an intake or exhaust even wrap up with a computer case one! 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