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Testing: How much do fan configs matter? Push vs Pull vs Push/Pull

2016-08-22
what's up guys Jays $0.02 here and I've done a lot of talking head videos where I just kind of talk to you and give you information to try and arm you with making you better pc builders and buy the right stuff for your builds because let's face it everyone has different needs and one of the videos I did I think it was last year maybe even the year before was I talked about fans and a difference between pull push and push pull and where you would want to use the various configs with fans and one of the biggest pieces of feedback I've gotten was it would have been nice to see actual comparisons and you know see it in actions you guys can actually tell what the difference is and not just talk about it so as we're going to do here today we're going to we're gonna talk a little bit about radiators we're talking about push-pull and we're going to actually do some comparisons here where we see how much of a difference there really is need a new x99 motherboard for your ultimate build well good news because as Rach has two new motherboards guaranteed to meet your needs with key features like 12 phase power delivery 3 steel PCI Express slots triple m 2 sockets and even a dedicated water pump header make the new x99 taichi and fatality x99 professional gaming i7 obvious choices for your next extreme bill learn more about as rocks line of x99 motherboards by clicking the link down below note I have right here are two different 120 millimeter fans both of them have a 120 millimeter surface area which is you know 12 centimeters by 12 centimeters and they have a 120 millimeter fan it fits on them that's how they get their name but the difference between both of these is their thickness this is a 30 millimeter radiator this is a 45 millimeter radiator which means this has 50% extra thickness to it which theoretically leads to it having more overall surface area in the fin density giving it a better cooling advantage to its skinnier counterpart so that's where fans come in where if you use a thick radiator but you don't have proper fan config on it you could actually be doing yourself a disservice and actually getting worse temperatures and going with a thinner radiator if you're not moving air across those fins efficiently the thicker the radiator is the more pressure drop there's going to be on one side versus the other as the air is going in it's going to meet resistance with all these fans because air actually kind of wants to expand and go sideways and as its forced straight through these it's going to lose pressure over distance so that's why high static pressure fans actually are recommended when it comes to radiators and that's why a push-pull configuration is recommended on anything 45 millimeter or thick in my opinion you'll find varying opinions out there on the Internet it's kind of funny how that works is there's lots of facts there's lots of opinions in a complete disregard for which ones which but I digress some would say a 60 millimeter or even an 80 millimeter would be where you would need to use push/pull not necessarily a 45 it's also going to matter on the fin density how small the fins are how big the fins are there's lots of factors there and I did a video on that as well that you could check out what you go more in depth on that I'm not going to bore you here today with that kind of information we're just going to kind of keep it high level and simple for the sake of apples-to-apples comparison here but as they as the air is pushed through the fins and forced to straight now it's going to encounter a lot of resistance which means that the pressure going on on one side may not equal the pressure on the other side and the goal here with radiators is to try and get equal air in air out on both sides of the radiator limiting the amount of pressure drop which would also limit the amount of cooling efficiency that you can have the way a radiator works is as water is flowing through the cooling tubes and the heat is being dissipated through those fins the fans job is to move that heat away from the radiator so that more heat can be absorbed so the more efficient you get the air across that radiator the better your radiator is going to work now yes guys I know there's obviously more to it than that there's also not only the thickness of the radiator there is the overall surface area of the radiator which means if you were to take 120 and add another 120 to it making it a 240 even though it's thinner it will have usually better cooling efficiencies than going with a radiator that's half as long but twice as thick so there's there's a lot of testing we can do here in lots of material that we can do in the future but I want to keep this video a manageable length so today we are going to focus on an all-in-one cooling loop that is built into my 1080 hybrid card because I showed in that video that I was able to improve the temperatures quite a bit by getting rid of the fan that it comes with and going with a high static pressure fan in a push-pull configuration so today we're going to test three things we're going to test we're going to test pull and then we're going to do a push-pull with my Vardar eighteen hundred and fifty rpm fans which are a high static pressure fan designed specifically for water cooling and radiators we're also going to try it at a bunch of different rpms to see how much difference there really is but I'm going to give you some predictions here now I don't predict that push or pull is going to be too different at the same rpm but I do predict that push pull will allow us to get better cooling at lower rpms and even better cooling at higher rpms the nice thing about push-pull is it doesn't mean you have to run the fans higher it means you can actually get away with lower rpms and not have to deal with nearly as much pressure drop across radiator alright that's enough talking head let's go ahead and turn around get into the test bench and let's start let's start playing around in testing this now what you guys are looking at right now is two identical EK water block Vardar 2200 rpm fans hooked up on a PWM splitter on the same PWM circuit so they are getting identical voltages here when it comes to fan RPMs and performance now the one on the left obviously is hooked up to a high density thirty millimeter thick 120 millimeter radiator and the one on the right clearly isn't an open-air config that has no resistance either in front or behind the fan so the reason why I'm showing you this is to kind of give you a visual aid as we increase rpms to see what happens in pull push and push pull config so that you can visually see what's happening here then at the end of all of this what I'm gonna do is off-camera I'll do all the temperature testing I'll put together a chart that way I mean there's really no way to entertain you while I check the temperatures I mean I would be really boring but anyway right now they are running at 1015 rpm of their max 2200 so they're less than 50 percent right now this is at their starting voltage this is as slow as they can spin so this as you can see we're getting like hardly any airflow through the radiator whatsoever right now and the open air as you can see is actually moving the paper now the paper does have a little bend at the end of it so that it doesn't just flop around and start waving we want to get something for the air to catch and push that way we can actually measure how much static pressure and airflow is making it through the fan blade and resist itself so as you can see it starting voltages there's quite a bit of difference between the two already but that should be fairly obvious let's go ahead and kick up the RPM a little bit let's go to about 1600 rpm and let's see if there's any difference so as you can see at 1600 actually fifteen hundred and ninety-one rpm I digress there is quite a bit of difference between the two you can see the fan on the oak the paper on the open-air fan is completely extended and that is just I do I can feel I'm standing quite a ways from these fans right now and I can actually feel the airflow from the fan on the right as you can see the paper it's no match for the fan it can lift it no problem so let's go ahead and see what happens here if we max out the RPMs and see what happens alright well there they are at a hundred percent fan speed as you can see the fan on the right obviously it's just like no problems it's even bending the paper that there's so much air hitting the end of that little tab that's actually folding the paper up in the middle but the radiator fan as you can see seems to be struggling now it's kind of interesting here what I'm noticing through the radiator fan is there seems to be a bit of a vortex taking place here and I wish I had smoke or something that I could show you I might have to invest in a fog machine and build a fan testing station actually show you this because what's happening here is the air actually seems to be kind of swirling around so it's being kind of almost pushed on by on both sides and let me show you what I mean by that if I lift up the paper it's actually being sucked back down now you physicist or whoever that follow me might be able to explain what's happening there the only thing I can think is it might have something to do with the venturi effect that's happening as the air is coming through the radiator and being forced to straight now and then suddenly reaching the atmosphere and allowing to swirl and do what it wants to do where the fan on the right is just kind of allowed to do its own thing there's no influence on the airflow the radiator is actually creating almost a bit of a suction effect where that's just where it goes if I lift it up it falls back down if I push it down it pushes back up so I can't actually explain that one now people might say the other fan on the right is actually influencing it it's not I've already tested this there's if I was to put something in between them there would be no difference what however on the airflow in fact I'll even point it away so as you can see there's no difference whatsoever when I do that but yeah when I lift it up it sucks back down but when I push it down it pushes back out so I don't know what's happening there but there seems to be a little bit of an influence happening right there can't quite explain it you guys tell me alright let's go and move to push config alright so same test this is a push config right now they are running at 1000 rpm as you can see obviously open air is winning but that should be no surprise but we want to see here is now in a push config are we going to get that weird venturi slash suction effect I inclined to say no but let's go and bump up the RPM alright so here we are at sixteen hundred and thirty rpm that's 75% on the voltage there and as you can see obviously the fan on the right completely unrestricted no change same test but pushed there we seem to be pushing the paper out a little bit now it doesn't really seem to be having that kind of a weird effect like you guys saw before so let's go ahead and bump it up to 100 and see if it pushes it out now rather than sucking it back down okay so same thing as before again guys these fans I promise are not affecting each other here I can put my hand right there as you can see there is absolutely no change whatsoever to that so the fan on the side is not influencing the radiator fan whatsoever but as you can see now we are getting a pretty decent airflow there through the radiator it's no longer got that weird kind of a venturi effect going there so I think something can be said for the interference of the airflow in a pool config versus push I've never actually tested this so this is news to me what if anyone's experienced this before but anyway one last test is go ahead and go over to push pool and then let's talk temperatures so there's what a thousand rpm looks like let's go ahead and bump it up to 1600 as the fans are ramping up let's see if you can see it push out it's at 1,200 1,300 1,400 and 1,600 so you can see there's definitely a little bit of improved airflow there obviously as we're expecting because we've got two fans working to overcome that pressure differential and now they're speeding up to 100% so let's see what happens here it's kind of funny even with two of these guys running at 100% they still do not seem to create nearly as much static pressure obviously as these fans perform in an open environment so yeah it's kind of kind of interesting there if you think about it I mean all fans are obviously tested in their most ideal condition which is completely open so you need to keep in mind when you shop for your fans their ratings when it comes to static pressure because you can have amazing airflow but it doesn't mean it can overcome the static pressure yeah guys I know I'm running airflow fans on my 560 red on skunk works I'm probably gonna be changing that on my update so give me a break all right let's do some temperature testing now the results are actually a little bit different than what I was expecting I actually expected pull to perform a little better than push you often here there can be a couple of degrees difference between the two which is very true and as my my charts here have shown but I was of the belief personally that pole would be slightly better because it has no choice but to pull air through the radiator watch I guess just seemed to make sense but with because if you look at the chart here you can see that push actually performed a little bit better than pull except at max RPMs where pull did a little bit better than push by a couple of degrees in fact pushed at 49 degrees Celsius max temp at max RPMs but pulled at 47 but if you take a look at push it did better in every other rpm range than max rpm so what I think might have been happening here because when I saw that result I did a little bit of checking a little bit of testing here was I felt a lot of air kind of pushing back against the intake of the fan if that makes sense when it's and push config what I think might be happening here is when you have a high fin density radiator and you have a high static pressure high rpm fan there could be a point where you can actually get a bit of splash or even back pressure because the air can't make it through the fins fast enough so it's got to find a way of least resistance which is going to be any of the cracks around the edge of the radiator where the fan meets and it doesn't you know actually touch flush or have any sort of foam protecting air from coming out besides because I felt some air actually coming back out the fan where it should be coming in so there was a little bit of what appeared to be a little bit of splash and air coming out the sides so not all of the air was actually going through the radiator we're in a pool config it was able to actually pull every single ounce of CFM through the radiator which gave us a little bit better performance but once you slowed the RPMs down that was no longer the case push was then the better performer at the 1600 rpm and 1000 rpm speeds so what I think might have been happening here like I said is a little bit of back pressure building up now obviously push-pull was the winner all around 41 degrees Celsius at 2200 rpm overclocked plus 100% on the voltage 2164 it's on the on the GPU plus 500 on the RAM I mean I really push the graphics card as hard as I could to try and build up heat but this is the first time I've actually shown you guys tangible results you can see by just how much anyway if you guys are looking at doing fan configs on your radiators if you can fit it push-pull is going to be the best result even at lower rpms as you can see we were getting lower temps at lower rpms than push or pull independently so if you have the room for it do push pull but if you don't then obviously make sure you have a good static pressure fan and temperatures will still be just fine anyway guys thanks for watching here I hope you enjoyed today's video we'll do more science stuff remember this these videos are directly in response to requests from you guys so make sure you let me know what you want me to do and if it makes sense then we'll do it anyway guys thanks for watching and as always we'll see you in the next video you
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