How To Choose A CPU Cooler

Finding The Best Fit

Gaming tower cases are often among the least restrictive in accommodating cooler size. Recent case designs have grown wider to accommodate tall tower-style CPU coolers, taller to accommodate top-panel radiators, and sometimes deeper to accommodate front-panel radiators. Relocated internal bays and the reduction or exclusion of external bays allows some case designers to maximize radiator space without increasing external dimensions.

Cases are still designed to flow front-to-back and bottom-to-top, but no longer use the power supply’s air inlet to supplement an undersized (80mm or 92mm) rear-panel exhaust fan. A larger 140mm or 120mm exhaust fan works in series with the CPU fan and front panel intake fan to direct heat from front to rear. Airflow can be reversed, but doing so fights against convective flow and disables the dust filters which are usually present only on a case’s front and bottom air inlets.

Certain low-cost cases don’t keep up with current design trends, however. As shown above, the heat pipes of a Big Air CPU cooler extend past the side panel of a traditionally sized mid-tower case. Maximum supported CPU cooler height is usually listed in a specification table on the case’s web page.

Cases aren’t always the limiting factor in CPU cooler selection, however. Zalman’s CNPS12X is designed to be offset ¼” towards the graphics card, so that it clears the top panel of most cases when installed on most motherboards. The design relies on the fact that many gaming motherboards have a vacant space where the top expansion slot is supposed to be. Since ours didn’t have that extra space, we had to mount the cooler backward (blowing rear-to-front) in order to test it on an open bench.

Another example, Thermalright’s 170mm-wide Archon SB-E has no offset and overhangs our graphics card slot in either orientation. Blowing towards the graphics card would have been an option if not for it hitting our memory. The design is once again optimized for motherboards that have no card in the top slot position, and further relies on the case’s top panel having some clearance above the motherboard. Both of those requirements are fairly common in gaming systems, but not ours.  

Anyone who thinks that putting a big cooler on a big motherboard might be a big problem needs only look downscale to see real trouble. Various mini ITX motherboards have unique limitations of installation space between the CPU socket and memory, any expansion card, voltage-regulator coolers, and the left edge of certain cases. Most wide, low-profile coolers are offset in at least one direction to maximize use of available space.

Some coolers are even offset in two directions. Note that the cooler below is designed to move the fan away from both the graphics card (offset left) and away from the front edge of the board (offset rear). Specifying these offsets in our reviews allows you to make an informed decision, or a very close guess, at which cooler is the most-appropriate for your motherboard.

Buyers unable to figure out any of these fitment issues can use a smaller cooler or, if their case has any space to mount any radiator, find a liquid cooling system to match that case.

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42 comments
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  • redgarl
    Blower GPU have worst quality coolers and provide lower OC capabilities. Not only that, but throttle and offer less stability... and are noisier...

    The only reason to buy one is because you overlooked the importance of a good case, and especially if you are planning on multi-gpu setups.

    I can only disagree with the writer finding open-air cooler defective. Best example in the news, the 1080GTX FE.
  • Mopar63
    Thomas, I actually did an entire set of experiments to see if, in the majority of scenarios, an open air cooler (which you said was defected) created any problems compared to a blower cooler.

    In my research any computer case with a good air flow design can easily handle an open air cooler. During my testing under full system load the internal air temperature of the case only raised about 3C with an open air cooler. Now if we assume a blower cooler is 100% efficient at removing the heat from the case then in this scenario the difference with internal temps would only be 3C.

    Now what do we get for that 3C increase in overall case temp? Well we see a pretty good reduction in GPU temp overall, plus we see much lower noise levels.

    That 3C BTW translated into a 3C increase of various motherboard components and no increase in CPU temps. What does this mean? Nothing as 3C is within margin of error and can be effected as much by ambient room temp and anything done with the cases air flow.

    Your premise that open air coolers are "defective" is false.
  • badirontree
    Most people prefer a cool GPU because in games you never use 100% of the cpu all the times... So it never gets hot to be a problem....
  • DonkeyOatie
    Horizontal motherboards and cube cases mitigate much of the mechanical issues of 'big air'. I have a Noctua D15S on a mATX board in a Thermaltake X21 case with a 4.6+ Ghz i7 4790K that is used for Science Fair projects and gets moved around a lot. I was prepared to replace the motherboard and go to liquid cooling, but the system has done well so far with middle school students handling it. They are trained to be careful (break it and you bought it).
  • Crashman
    251426 said:
    Blower GPU have worst quality coolers and provide lower OC capabilities. Not only that, but throttle and offer less stability... and are noisier... The only reason to buy one is because you overlooked the importance of a good case, and especially if you are planning on multi-gpu setups. I can only disagree with the writer finding open-air cooler defective. Best example in the news, the 1080GTX FE.
    Disagreeing doesn't make you right though. Nvidia put a bunch of effort into its top blower cooler and it worked very well. Dumping that heat into your case isn't simply a bad idea, it's the kind of idea that makes me question your judgement on just about anything. And getting five upvotes from people with equally poor judgement isn't going to change my analysis.

    2153694 said:
    Thomas, I actually did an entire set of experiments to see if, in the majority of scenarios, an open air cooler (which you said was defected) created any problems compared to a blower cooler. In my research any computer case with a good air flow design can easily handle an open air cooler. During my testing under full system load the internal air temperature of the case only raised about 3C with an open air cooler. Now if we assume a blower cooler is 100% efficient at removing the heat from the case then in this scenario the difference with internal temps would only be 3C. Now what do we get for that 3C increase in overall case temp? Well we see a pretty good reduction in GPU temp overall, plus we see much lower noise levels. That 3C BTW translated into a 3C increase of various motherboard components and no increase in CPU temps. What does this mean? Nothing as 3C is within margin of error and can be effected as much by ambient room temp and anything done with the cases air flow. Your premise that open air coolers are "defective" is false.
    You're implication is that a case should be made noisier to remove GPU heat, and use a quieter GPU cooler to compensate. But if you blow the heat out the back, the extra noise can be taken care of by a case with fewer, more strategically located vents. And the 3C difference meant something to me in the SBM series :D
  • Dunzaus
    Praising liquid cooling as much as you so is misleading. You talk about what can happen with a big air cooler ( if it get shipped =/ or mishandled ) , but you don't care to mention what will happen if your liquid cooling system starts leaking water.

    I'm sticking to air cooling, because I have seen too many youtubers that really knows what they are doing with computers, like linustechtips, and still having leaks.
  • bit_user
    I like downdraft coolers, for their added cooling of VRM (when it was separate), RAM, and chipset. A good downdraft cooler can easily handle a 130 TDP CPU.

    As for radiator placement, I think the best location would be to exhaust out the side, near the bottom. That way, it gets cool air and can run the fan slowly. This would allow hot air still to be exhausted near the top of the case.
  • Crashman
    2193724 said:
    Praising liquid cooling as much as you so is misleading. You talk about what can happen with a big air cooler ( if it get shipped =/ or mishandled ) , but you don't care to mention what will happen if your liquid cooling system starts leaking water. I'm sticking to air cooling, because I have seen too many youtubers that really knows what they are doing with computers, like linustechtips, and still having leaks.
    We haven't, at least not visible leaks. Our leakage problem has been microscopic leaks that cause a cooler to dry out after around three years. We recommend air coolers for most stationary systems.
  • bit_user
    8708 said:
    251426 said:
    Blower GPU have worst quality coolers and provide lower OC capabilities. Not only that, but throttle and offer less stability... and are noisier... The only reason to buy one is because you overlooked the importance of a good case, and especially if you are planning on multi-gpu setups. I can only disagree with the writer finding open-air cooler defective. Best example in the news, the 1080GTX FE.
    Disagreeing doesn't make you right though. Nvidia put a bunch of effort into its top blower cooler and it worked very well. Dumping that heat into your case isn't simply a bad idea, it's the kind of idea that makes me question your judgement on just about anything. And getting five upvotes from people with equally poor judgement isn't going to change my analysis.
    Wow, self-righteous much?

    Just look at the industry. If blowers were the ideal solution for cooling on air, why isn't everyone using them, especially in the higher-end cards? Maybe you think all the OEMs building graphics cards are idiots and can't learn from their decades of experience?

    What if Nvidia only uses blowers as a safe bet - to mitigate against people with poor case circulation - as redgarl mentioned? Or maybe because they're cheaper, having only 1 fan, and Nvidia is content to let their OEMs worry about more elaborate cooling solutions that allow the GPU to stretch is legs?

    Blowers have one disadvantage I haven't seen mentioned, which is negative pressure. By exhausting out the back, they suck a lot of dust into your case, especially if you have a multi-GPU setup. The way to combat this is with dust filters and positive pressure, but the blowers mean you need high intake CFMs, which will turn your PC into an absolute wind tunnel and clog your dust filters very quickly.

    I agree with Mopar63's conclusion, which is that open air cooling doesn't raise case temps much, and case temps aren't really a limiting factor for anything. So, while it seems less elegant than to exhaust the waste heat, it is an exercise in optimizing the limiting factor, which is nearly always GPU temps. So, it works out that if you're not going with water cooling, your best bet is open air and decent case airflow.

    Normally, I prefer rational argument to downvotes, but your tone has earned you my downvote. As a site staff member, you might think more about how to interact with readers. You are in a privileged position of controlling what's in the article, so if people disagree with you, there's no need to get nasty. All of the other writers I've seen comment in the forums seem to understand this.
  • redgarl
    8708 said:
    251426 said:
    Blower GPU have worst quality coolers and provide lower OC capabilities. Not only that, but throttle and offer less stability... and are noisier... The only reason to buy one is because you overlooked the importance of a good case, and especially if you are planning on multi-gpu setups. I can only disagree with the writer finding open-air cooler defective. Best example in the news, the 1080GTX FE.
    Disagreeing doesn't make you right though. Nvidia put a bunch of effort into its top blower cooler and it worked very well. Dumping that heat into your case isn't simply a bad idea, it's the kind of idea that makes me question your judgement on just about anything. And getting five upvotes from people with equally poor judgement isn't going to change my analysis.


    Arhmm... first off dumping air in your case isn't really a matter if, like me, you have a Fractal Design R2 XL with optimal airflow + a fan controller. I removed my HDD cage and put all my storage in my 5.25 bays. Also, I am having 7 fans exhausting heat from front to rear and bottom to top + a side fan for my CF setup.

    Now for graphic cards... the 1080 GTX FE throttle when the temps are getting too high. A simple OC is resulting in worst performance however not with the open-air cooler. Gigabyte is having a card with 170 MHz OC off the bat and temps of about 20C less.

    Finally, what is going to make your system crash, is your GPU temp over anything else. So investing in an open-air cooler make sense, not the other way around. Blowers are used because they are cheaper and were the first type of proven coolers, that's it.
  • lordmogul
    2153694 said:
    Thomas, I actually did an entire set of experiments to see if, in the majority of scenarios, an open air cooler (which you said was defected) created any problems compared to a blower cooler. In my research any computer case with a good air flow design can easily handle an open air cooler. During my testing under full system load the internal air temperature of the case only raised about 3C with an open air cooler. Now if we assume a blower cooler is 100% efficient at removing the heat from the case then in this scenario the difference with internal temps would only be 3C. Now what do we get for that 3C increase in overall case temp? Well we see a pretty good reduction in GPU temp overall, plus we see much lower noise levels. That 3C BTW translated into a 3C increase of various motherboard components and no increase in CPU temps. What does this mean? Nothing as 3C is within margin of error and can be effected as much by ambient room temp and anything done with the cases air flow. Your premise that open air coolers are "defective" is false.


    3°C on the graphics card can be the difference between archiving the maximum boost speed and a reduced clock if these 3°C fall into the threshold.
    Besides that it's nothing to be concerned about even though some people try to convince others that it might be the difference between life and death.
  • none12345
    Im going to also disagree about the open air coolers being defective.

    I personally do not care about dumping heat in the case, i want the GPU as cold as it can be, as its usually the bottle neck.

    Of course i also dont run with a closed case under a desk either. Its open sided with nothing next to it, so dump away!

    I really dont care if its a blower or open air cooler tho. Whatever cooler gives better thermals with better acustics wins. Simple as that.
  • Sam Hain
    I disagree with the portion of the article, referring to top-mounted radiators; "... and radiators placed there usually work best with the fans underneath, blowing upward."

    Pulling cool-air in from outside the case over the rad has advantages that outweigh drawing hot-air from inside of the case through it

    - Lower CPU temp achieved due to COOL air being supplied
    - Acts as another "intake" source of COOL air for your rig, where as your front intake
    fan may not be able to reach
    - Depending on case design, acting as an intake may prove to be better for intake-to-
    exhaust air flow

    In my xp with closed-loop coolers, this has always been the case with top-mounting. Others may have had different results with exhaust setups but I'd be surprised if so...
    -
  • turkey3_scratch
    Just one thing I'd like to point out, in the very introduction you state "Electrical semiconductors have the unusual trait of being able to switch between low and high resistance when electrical current is applied in a certain way", however, it is not the current that is applied but it is the voltage.
    http://amasci.com/amateur/transis.html
    Quote:
    To turn on an NPN transistor, a voltage is applied across the base and emitter terminals. The base current is not important to transistor operation. It's just a byproduct of the REAL operation, which involves an insulating layer called the Depletion Region. By focusing attention on the current in the Base lead, most authors go up a dead end in their explanations. To avoid this fate, we must start out by ignoring the base current. Instead we look elsewhere for understanding.
  • TJ Hooker
    @turkey3_scratch FYI that article is talking about bipolar junction transistors (BJT). Most modern digital ICs, like CPUs, use field effect transistors (FET). That being said, FETs are also voltage controlled devices. However, turning a FET on or off involves charging/discharging the gate capacitance (through applying a voltage), which one could argue constitutes "electrical current applied in a certain way".

    As an aside, after skimming that article I'm not sure how I feel about that source. The author seems like someone who thinks being a contrarian somehow means you're smarter, i.e. "But if you DO manage to decode my explanations and crude ASCII artwork, I think you'll be in the elite minority who really understands transistors". Same with the way he feels the need to provide his own definitions/explanations of the flow of charge, resistance, etc. Not that what he's saying is wrong, but he seems like he's deliberately going against convention for sake of trying to sound edgy and smart. Finally, I swear that I heard a good explanation of why the emitter current really is 'controlled' by the base current, in a class on semiconductor physics, contrary to what that author is claiming. Unfortunately I can't remember :/ Maybe I'll try and take some time to brush up on it.
  • Allen_7
    so how to know if there is water leakage?
    if the temperature remains in a normal level, can I assume there is no leakage yet?
  • nitrium
    8708 said:
    You're implication is that a case should be made noisier to remove GPU heat, and use a quieter GPU cooler to compensate. But if you blow the heat out the back, the extra noise can be taken care of by a case with fewer, more strategically located vents. And the 3C difference meant something to me in the SBM series :D

    Case fans are far, far quieter than GPU blowers! A couple of 140mm fans at 800-1200 rpm makes almost no noise and shifts incredible amounts of air through the case, whereas a blower GPU at 4500 rpm sounds like a jet engine. I'll take an open air GPU cooler and two big case fans any day, despite a nominally higher case temperature - you get a cooler GPU and a far quieter system.
  • Crashman
    328798 said:
    8708 said:
    251426 said:
    Blower GPU have worst quality coolers and provide lower OC capabilities. Not only that, but throttle and offer less stability... and are noisier... The only reason to buy one is because you overlooked the importance of a good case, and especially if you are planning on multi-gpu setups. I can only disagree with the writer finding open-air cooler defective. Best example in the news, the 1080GTX FE.
    Disagreeing doesn't make you right though. Nvidia put a bunch of effort into its top blower cooler and it worked very well. Dumping that heat into your case isn't simply a bad idea, it's the kind of idea that makes me question your judgement on just about anything. And getting five upvotes from people with equally poor judgement isn't going to change my analysis.
    Wow, self-righteous much? Just look at the industry. If blowers were the ideal solution for cooling on air, why isn't everyone using them, especially in the higher-end cards? Maybe you think all the OEMs building graphics cards are idiots and can't learn from their decades of experience?

    They're making them because you're buying them. And you're buying them because people are telling you to. And people are telling you to buy them because they're quieter. But then you need more case ventilation, and that means you lose most of your noise advantage.

    In other words, if you were buying blue cards, they'd be selling blue cards. If you were buying cards with rusty metal covers, they'd sell you cards with rusty metal covers. Engineering has nothing to do with it.

    328798 said:
    What if Nvidia only uses blowers as a safe bet - to mitigate against people with poor case circulation - as redgarl mentioned? Or maybe because they're cheaper, having only 1 fan, and Nvidia is content to let their OEMs worry about more elaborate cooling solutions that allow the GPU to stretch is legs?
    Chris Angelini wrote a huge piece about the huge expense Nvidia put into designing its better-performing cooler, something like 4 years ago. The coolers you prefer are easier and cheaper to design, cost less to produce, and OEMs are extra happy to give you a cheaper cooler that's lighter to ship.

    328798 said:
    Blowers have one disadvantage I haven't seen mentioned, which is negative pressure. By exhausting out the back, they suck a lot of dust into your case, especially if you have a multi-GPU setup. The way to combat this is with dust filters and positive pressure, but the blowers mean you need high intake CFMs, which will turn your PC into an absolute wind tunnel and clog your dust filters very quickly.
    Wait, you'd better rethink your plan on cooling then. Most cases also have an exhaust fan behind the CPU. You could have two intake fans to match the CPU and GPU, but...hey, if you're looking at better case airflow to cool your box-heater, you're clogging up dust filters anyway.

    328798 said:
    I agree with Mopar63's conclusion, which is that open air cooling doesn't raise case temps much, and case temps aren't really a limiting factor for anything. So, while it seems less elegant than to exhaust the waste heat, it is an exercise in optimizing the limiting factor, which is nearly always GPU temps. So, it works out that if you're not going with water cooling, your best bet is open air and decent case airflow.
    Great. My experience shows otherwise. That is, my experience. Not a bunch of talking, a bunch of building. Your experience might be different.


    328798 said:
    Normally, I prefer rational argument to downvotes, but your tone has earned you my downvote. As a site staff member, you might think more about how to interact with readers. You are in a privileged position of controlling what's in the article, so if people disagree with you, there's no need to get nasty. All of the other writers I've seen comment in the forums seem to understand this.

    Actually, I'm writing for other people. As in, those who care about how things work rather than how they wished they would work. It's like when the entire High School Auto Shop told me that the 205/50's I wanted for the front of my car were wider than the 275/60's I wanted in back because they had the firmly held belief "50's are wider than 60's": I take your downvote as a compliment, it means I've gotten my point across.
  • Crashman
    1687881 said:
    3°C on the graphics card can be the difference between archiving the maximum boost speed and a reduced clock if these 3°C fall into the threshold. Besides that it's nothing to be concerned about even though some people try to convince others that it might be the difference between life and death.
    I actually cared mostly in the System Builder Marathon because it was the difference between 4.4 GHz and 4.5 GHz in a performance competition. All of my cards had enough cooling, it was the CPU that ran hot when an even bigger CPU cooler would have broken budget.

    But we'll just keep that between us :)
  • nitrium
    8708 said:
    They're making them because you're buying them. And you're buying them because people are telling you to. And people are telling you to buy them because they're quieter. But then you need more case ventilation, and that means you lose most of your noise advantage.

    That's absolute nonsense, and I suspect you know it. Big case fans (140 mm) are effectively silent and shift far more cfms than small loud GPU blowers. Open air GPU coolers are in most cases more effective than blowers IF the case is sufficiently vented with fans - and that can be trivially achieved with practically no additional acoustic overhead.
  • Ohio Joe
    I consider any CPU or video card that needs water cooling to be defective. Also video cards that are a foot long and need three fans....defective.
  • Mopar63
    8708 said:
    You're implication is that a case should be made noisier to remove GPU heat, and use a quieter GPU cooler to compensate. But if you blow the heat out the back, the extra noise can be taken care of by a case with fewer, more strategically located vents. And the 3C difference meant something to me in the SBM series :D


    The assumption of that implication are wrong. I have built many open air based GPU systems with great air flow cases and near silent operation even under load. The specific testing I mentioned was with a Fractal Arc mini using a Sapphire 290X Tri-X card. The case fans where three 120 mm fans, 2x front and one bottom for intake and all set at 5 volts. The system was silent for all practical purposes.

    As for the 3C, are you referring to 3C making a difference in ambient case temp or specific component? Finally note I mentioned the difference would be 3C IF a blower cooler had a perfect ability to remove heat, which none do. Also that 3C was total case temp rise, it includes heat from CPU, motherboard and so on.

    Again I am just saying I think your position that open air coolers are defected is wrong.
  • ubercake
    I like the AIO liquid coolers because it's so easy to work around the motherboard without a giant heatsink over the CPU/RAM area. I have to use a butter knife to push the PCIe release lever when I change out video cards because my NH-D15 won't allow a finger in between the heatsink and my video card in the first slot. I also have to remove a fan to swap out RAM.

    The reason I deal with the inconvenience of the massive hunk of metal that is the NH-D15 is because I haven't found an AIO cooler that cools more effectively or - more importantly - more quietly.

    As for GPU cooler... I have used a blower style / vapor chamber (exhausting out the back) since the GTX 580. I have no problems with heat or throttling. I just use a custom fan profile a tad steeper than the default. My 1080 core clock runs at 1886MHz regularly without an OC (playing Witcher 3). The blower fan is extremely quiet. My case always maintains positive pressure which keeps things close to dust-free.

    I think everyone's situation is different with regard to whether blower-style or open-air coolers on GPUs work better. The blower fan on doesn't emit as much noise as a standard fan of equal size because the air isn't blowing in the same direction as a standard fan would.

    As a general rule, I've found the fewer fans you can use, the less noise. The larger the fan, the quieter. If you don't OC anything, it's easy to keep temps well below spec with fewer fans. I try to use as few fans as possible. You have to try a lot of different combinations before you find what works for you. Personally, even though I like the look and workspace better with AIO liquid CPU coolers, I've found AIOs I've tried run a lot louder than the NH-D15.
  • Mopar63
    8708 said:
    328798 said:
    I agree with Mopar63's conclusion, which is that open air cooling doesn't raise case temps much, and case temps aren't really a limiting factor for anything. So, while it seems less elegant than to exhaust the waste heat, it is an exercise in optimizing the limiting factor, which is nearly always GPU temps. So, it works out that if you're not going with water cooling, your best bet is open air and decent case airflow.
    Great. My experience shows otherwise. That is, my experience. Not a bunch of talking, a bunch of building. Your experience might be different.


    Did you seriously go there? Did you not notice my original post when I explained testing this theory. I spend a few DAYS working through build settings to test this and a few days before that figuring out the best way to test the scenario and ensure the results had meaning.

    I have built in 30+ years of computer experience THOUSANDS of systems and did not one day wake up and come to this conclusion. My results where reached through a proper test methodology and observation plus going over results. I was a reviewer for almost 20 years and to have you claim my position is "talking" is insulting to say the least.