H100 push/pull with different fans idea

Ok then i got a bould coming up including the HAF XB case and a H100 that i want to run in push/pull.
The thing that's different tho is that i want to run two sets of different fans on the H100 as seen below:



As you can see the plan is to use the AF (Air Flow) fans on the back of the rad so it can blow the cold air into the case after it cooled the rad.
Has anybody ever done this before as well or?

Let me know what you guys think about this ^_^

Id want to stick with 2 of the same type of fan. Having 2 different types blowing different pressures might not work as well.

yeah stick with the same fans if you use different ones, it will create turbulence and that turbulence will create noise

Tripp said:

yeah stick with the same fans if you use different ones, it will create turbulence and that turbulence will create noise

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Thats what i was afraid of yeah, so i think i'll got with 4 AF fans instead because i WANT airflow going into the case ove the MOBO and towards the GPU as well.
Not sure if i will install a 200mm fan in the top as well or just let the huge mesh area do the trick and allow to look into the case as well.

Would be a fun experiment for TinyTOmLogan to do tho, since he has tons of the SP and AF fans laying around :lol:

no stick with static pressure an just use your rear exhaust as an intake if you are that worried mate

edit: never use your rad as an intake always an exhaust

Tripp said:

no stick with static pressure an just use your rear exhaust as an intake if you are that worried mate

edit: never use your rad as an intake always an exhaust

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I disagree with this. Im running mine with fans under the rad (mounted in top of my 500R) pulling the air in thru the rad and into the case. Axial fans suck better than they push so this is how they work best. Im able to run my H100 at the lowest setting and it runs at virtually silent speed even with this 8150 overclocked! I tried it this way as well as on top pushing (intake) and on bottom pushing (exhaust) and this is the way they worked best by 3C!

well really you don't want to be pushing hot air into your case (as heat rises anyway so your working against the way it wants to go), as your trying to take the heat away so that sounds a bit weird to me

It does sound weird, I totally agree. I can put my hand under the fans while running OCCT and the air is still pretty cool. Its moving thru the rad fast enough that its not getting heated up. This way, youre also keeping the coolest air possible running thru the rad. Ive got enough case fans running so theyre directing the heat out the back of the case so rising heat doesnt seem to be an issue.

When I first got this H100 I tried it with the fans on top pushing air down into the case, fans on the bottom pushing air up out of the case and with the fans on the bottom pulling air into the case was the coolest by 3C. I know that doesnt sound like a lot but when youre going for max overclocks, 3C is huge!

I agree that it doesnt sound logical though, but it works.

That is very strange indeed

Xenomorphical said:

Ok then i got a bould coming up including the HAF XB case and a H100 that i want to run in push/pull.
The thing that's different tho is that i want to run two sets of different fans on the H100 as seen below:

As you can see the plan is to use the AF (Air Flow) fans on the back of the rad so it can blow the cold air into the case after it cooled the rad.
Has anybody ever done this before as well or?

Let me know what you guys think about this ^_^

Click to expand...

I'm not sure this diagram is correct , SP fans are designed for a radiator setup and are supposed to move more air than AF fans. And as the others have said it's best if you have an h100i mounted in the roof to have the fans set to exhaust air out of the roof. If you do push/pull use SP fans , the standard 120mm SP QE fans spin at 1450rpm and the 120mm AF QE spiin at 1100 rpm. So it's not a good idea to mix fans with different rpm ratings.

The mixed type of fans idea is long gone right now so no worry's there peeps.
The thing is, this is the planned case to use for the rig:




In addition to the pics, the rig will be running with everything at stock settings with a i7 3820 @ 3,6 Ghz.
About not using the H100 a a intake a aggree with the top mounting position of regular cases.
But since this will be a front mounted situation i do not think it will that will go up in this case.

Also, i got two systems running with the same i7 CPU at stock settings as a main air inlet in a CM Trooper in the sidepanel and a C70 in the front.
and temps never went over 35 degrees C after hours of gaming (planetside 2/crysis 1&2/ Skyrim)
In the CM storm i'm using 4 cooler master sickleflow fans and in the C70 just the two stock fans on medium settings.

As for the SP and AF part, these are my thoughts:
SP: Static Pressure, focused at a short distance to cool a surface they are mounted on.
AF: Air Flow, a paralel jet of air blowing deep into the pc case.

I could be wrong tho but thats what i made out of it after watching Tom';s vid :huh:

AF fans come with the description, used for areas of unrestricted air flow so exhausts. You what sp fans for intakes and rads.

I would mount the h100 at the top as an exhaust and turn the rear case fan as an intake cool air comes in the sucked right into the rad. If you pull air in from the top not only are you fighting thermal dynamics but I'll be pulling dust in to the rad and case.

vorticalbox said:

AF fans come with the description, used for areas of unrestricted air flow so exhausts. You what sp fans for intakes and rads.

I would mount the h100 at the top as an exhaust and turn the rear case fan as an intake cool air comes in the sucked right into the rad. If you pull air in from the top not only are you fighting thermal dynamics but I'll be pulling dust in to the rad and case.

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There is no top mounting options for a H100 with the HAF XB case, only a 200mm fan.
I will b going for 4 SP fans for the rad then, and re-use the fans that come with the H100 and the HAF XB to go in the back of the case.
After some temp testing i will decide if the rear one will be blowing into the case or sucking air out the back.

It just sucks right now i have to wait a month untill i get the green light to order all the parts

Cooler Master seem to suggest the rad fans always exhaust out of the case. Another thing to consider - I have the h100 (stock fans) and an Asus DCII HD7950 - and had to mount the fans in the plastic front area and the rad just inside the case for everything it to fit. If you're hoping to push/pull, you definitely want to make sure you don't have an oversized graphics card.

I've currently found that a 200mm in the roof, rear 120 and the rad fans all in exhaust, and letting the air find it's way into the case without help seems to work best (my graphics cards just seem to throw hot air everywhere, a rear exhausting graphics card would maybe make a difference to how it's set-up).

Gotta say though, overall I'm very happy with the case - yes it's not going to make a quiet PC, but it's fun, quirky and so easy to swap components on the motherboard.

- you could probably mount the H100 in the roof, but it'd be either a way cool mod, or a proper Heath-Robinson affair.

I guess i have a bunch of setups with different fan position and intake /outtake combinations to try out.
I was going to get a 200mm fan in the roof as well and the GPU will be something along a GTX 660 so that should fit just fine ^_^
Thanks for the input tho, i'll make sure i try it out when i got all the parts!

Not to hijack the thread, but what about with the HAF X, with the SP fans in a P/P and 2 200mm fans on top of that in the roof. Will that mess with anything on an H100i?

I got to discussing this on the HardOCP forum and decided to do a little half assed experiment with a car AC thermometer I had. I ran OCCT and got the temps up to around 50C after a few minutes then sat the thermometer on top of the case where the fans are pulling air into the case thru the rad. The ambient air temp was around 72F.



Next I held the thermometer directly under the fans inside the case until the temp stopped rising. It pegged out about 78F.



So thats around 6F or 3C. While that is warmer, I dont think its that big a deal as I have 2 front intake fans, a 200mm side intake fan, bottom intake fan and of course exhaust fans. I dont think the 3C warmer air coming thru the rad is enough to bother anything as I dont have any unusually warm readings with Thermal Radar. If you have proper case fans handling air flow, the warm air is going to be moving thru the case fast enough that its not going to affect anything. So in the end, I think its more important to have the coolest air you can get, flowing thru your rad. And since axial fans suck better than blow it makes me think having them under the rad pulling air in works best. And since Im able to run my 8150 with a very solid overclock and keep my fans on the slowest most silent speed setting, I think it works.

Also keep in mind the AC thingy reading might be higher because you ware holding it, so your body temp might have heated it up.
Conclusion on this tho is using a rad as a additional air intake is fine aye?
This since the air goes trough it fast enough not to become hot air.

Everyone is so smart but you are all thinking ahead of yourselves..

Everyone is SO quick to assume that the same fan would be better without actually using logic when taking a lot into consideration.

Fans made for static pressure only perform better when something is in front of them.... :mellow:

So the SP fan would be good to use for PUSHING the air into the Radiator.

The AF fan would be better at pulling.

Using the same fans in both push and pull would cause the pull fan to out perform the push fan no matter what fans you use because there is nothing blocking the airflow of the pull fan, it will obviously blow a higher cfm..

Also take into consideration that even an SP fan will be hindered by having a radiator in front of it.

So the real answer to this mystery can be found using a very common problem solver we like to call math.

You have to take a lot into consideration.

The higher CFM/SP fan will be better as the push fan because it will allow for better airflow

The airflow fan will be better for the pull fan because there will be nothing blocking its airflow and will be able to perform how it is meant to.

Whichever fan you use will have its CFM drop the higher density of the Radiator/Heatsink. Which means you want to use a higher RPM fan as the push and the LOWER RPM fan as PULL.

Some math must be done to figure out the curve.

Example:

Your SP fan is pushing 40cfm through your radiator at 1500 rpm. If the SP wasnt pushing through the radiator at 1500rpm and had nothing blocking its airflow, it would achieve a higher CFM (lets say 60cfm).

Take your AF fan and find out at what speed it will get the same CFM (40cfm) without blockage. Chances are the af fan will only have to run at about 1300 RPM to achieve 40 CFM. So that would mean a fan that runs at 1300rpm and pushes 40cfm without blockage should be your choice for pull.

An SP fan that pushes 40CFM at 1500 rpm can be your second choice.

So the Pull fan does NOT need to be optimized for pressure.

It does NOT make sense to use pressure fans as PULLERS.

It does not make sense to use the SAME fans for push/pull (unless you lower the RPM of the PULL) because the pushers performance will be hindered due to the radiator blocking it. which will turn your matching RPM/CFM Fans into unmatching fans..

You want to match your CFM of your unblocked pull fan to the CFM of your blocked PUSH fan.

Think before you write things people.. And don't be so quick to assume things without thinking them through. ^_^

Figure out your CFM Curve and match your CFM. Do not match your fans unless you can use a fan controller to turn the RPM of the pull fans down a bit to match. :mellow:

I will say it one more time in case anyone couldn't understand my rant.


The RPM of the fan doesn't matter. what matters is what CFM you get in what circumstance.

If you use the same fan at the same RPM you will not achieve the same CFM with both push and pull fans.

The PUSH will have the lower CFM.

This is bad.

It is much better to mix and match fans or lower the speed of your pull fan to match the CFM of your push.

You may be able to accomplish this using sound as a reference, but this will be hard for anyone who has little experience with fans. :lol:

Cheers EVERYONE! And I hope I made you all think about this a little differently.

Actually, it was found that using airflow optimised fans in the pull part of push/pull worked better - Ill try and find the LinusTechtips video.

Ive tested it my self also, on the H55 which cools my GPU I have tried 2x SP 120 (in push pull)vs 1 SP 120 in push and 1 Arctic cooling f12 (airflow) in pull exhausting out the case and the later works better.