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Push/Pull vs push vs pull for Radiator?

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iLoki

Member
Joined
Dec 8, 2008
What is the best way to keep a decent airflow through a radiator?
I'm going to get a swiftech mcp220qp (haven't decided on built in res or micro res yet), but I am curious as to whether a push/pull set up will actually work better than a push set up? It seems to me that the fans would have to be designed to work in such a fashion for it to provide any real benefit. I'm debating whether to get the extra fans, I currently have a couple of 120mm 100+ CFM fans as my intake, that I plan to use on the radiator, since the radiator is going to obstruct them anyway. Would adding the extra fans to the back of the radiator prove useful at all?
 
LOL not with 100+ CFM fans it wont... not anything noticeable anyway. If you were running 40 CFM fans, then perhaps the push/pull would make a difference.
 
Ya lol obviously I don't care much about noise... I've got 3 of those fans plus my 2 9800s plus my CPU HSF with a 92mm fan on it =) oh and don't forget the 200mm BigBoy on top :D

thanks for the info, looks like I will be doing the high speed push with ~30mm shroud :D
 
Ya lol obviously I don't care much about noise... I've got 3 of those fans plus my 2 9800s plus my CPU HSF with a 92mm fan on it =) oh and don't forget the 200mm BigBoy on top :D

thanks for the info, looks like I will be doing the high speed push with ~30mm shroud :D

Although you say the sound doesn't bother you, you may be surprised at just how nice it is to sit at your computer and NOT hear a jet engine next to you. The Swiftech rads work VERY well with med CFM (quiet) fans. Changing from 1500RPM/28db Yate loons to Kaze Ultra 3000's/40db only netted a 2-4C difference in cooling, with a properly sized rad. If you REALLY want that extra 2-4C at the cost of the noise, then by all means go for it. If you wanted to push/pull, i'd definitely go for some LOW flow 1300 RPM Yates on either side. The added benefit of WCing is that you now get to move heat output from one of the biggest heat producers away from your important parts. What this means is, you can use quieter fans in the case.

Axis
 
The best configuration for fans is a pull. push/pull creates turbulence and noise which will kill any benefits. In my experience, fans like resistance of pulling rather than pushing, but it is important to have pressure in there somehow.
 
The best configuration for fans is a pull. push/pull creates turbulence and noise which will kill any benefits. In my experience, fans like resistance of pulling rather than pushing, but it is important to have pressure in there somehow.

You're saying push/pull is worse than pull only? :eek:. According to martin
2 fans Push/Pull vs others - It was very clear that when using two fans per radiator section, that the radiator intself acts as a flow spreader and provided great benefit to straightening out the air for the second fan in a push/pull configuration. Just like doubling up with a pump, there is a pressure benefit to doubling up on fans and this translates to about a 20-30% performance gain. The added fan pressure simply means and added gain in air flow and corresponding performance. None of the experimental pull/pull or push/push configurations provided any noteworthy benefit as it seams the air is simply too disturbed from the first fan to allow the second to perform properly when air is moving. I would always recommend a push/pull configuration for two fans and add a shroud to both sides if space allows.
 
how loud are the medium yl's?

They sound like this ................. :santa:

They are very quiet but it depends on your reference. I think they are rated at 33db which isn't bad at all. For the price of 3 yate loons, you can add a Sunbeam 4 channel fan controller and still come out cheaper than 3x of most other fans alone.

Axis
 
Well, I've already got some high speed fans, and the push/pull in martins review worked best with low speed fans. I plan to use a shroud and a push set up for now, and maybe after a little while try a push/pull with another shroud on the other side.
 
You're saying push/pull is worse than pull only? :eek:. According to martin

Unfortunately that is what I said..that is the problem with a lack of good proofreading. I meant to say push/push and pull/pull, and somehow between thinking and typing that got shorten to push/pull. In seeing the push/pull comment I stopped. :bang head

I am glad you caught that before anyone took that advice. I agree with you (and martin) that push/pull is better than just one fan in either configuration.
 
Thanks, Gillbot, I will keep that in mind! the fans I'm using were pretty cheap, so maybe I will buy new fans anyway...
 
They sound like this ................. :santa:

They are very quiet but it depends on your reference. I think they are rated at 33db which isn't bad at all. For the price of 3 yate loons, you can add a Sunbeam 4 channel fan controller and still come out cheaper than 3x of most other fans alone.

Axis


I just bought 10 of these for my rads and let me tell you, they are SWEET!!!

I can hardly hear them and they are outside the case.
 
Not all "100cfm" fans are created equal. Many of the lower cost, higher rated flow fans don't work well when they need to move air through a restriction such as a radiator.
Exactly. If they are the san ace fans, they are the real deal. All too often though, you get mfgrs. claiming 100CFM @ 28dBa to which I say, #@!@ ##$%!
 
From what i've always been told, not just with water cooling PCs, but with any fan/rad, always pull instead of push. When you push air against a rad, the air itself adds more resistance. (Ok, thats just my theory, but it makes sense at a molecular level! :D). In practice, there probably isnt a big difference between push and pull, obviously push and pull is going to be better, as you have more static pressure.

Which i'll make my last point. CFM is the LAST thing you should be worried about. CFM ratings of fans, like the GPH rating of pumps, is with 0 resistance. If you buy cheap 100cfm, i guarantee you will never see 100cfm out of that fan. The rating that matters most, is the Static Pressure.

*Hugs his san aces*
 
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