Push-Pull on TRUE, S-Flex and mounting (pics if possible)

[Demo]

Im considering a S-Flex 1600RPM for my TRUE120ex and im wondering how much lower temps i would get if i add another S-Flex 1600RPM to pull air, next issue is how can i easily mount the 2nd S-Flex w/o purchasing another retention clips ( if you guys can post pictures on how you mounted your push-pull config that would be great )

[Izvire]

Im considering a S-Flex 1600RPM for my TRUE120ex and im wondering how much lower temps i would get if i add another S-Flex 1600RPM to pull air, next issue is how can i easily mount the 2nd S-Flex w/o purchasing another retention clips ( if you guys can post pictures on how you mounted your push-pull config that would be great )

The easiest way probably is using zip-ties. I've used zip-ties both on my GPU and my CPU. Hope you can get a clue from this pic:

[OS-Wiz]

I'm using the newer version of the TRUE LGA1366, it came with a shroud mount and the clippy thingies. Using two fans in push pull, I've a 1-2c lower cpu temp at idle and 2-3c lower at load. But what I like best is the fact that should one fail, another is hopefully still working!

[Demo]

Wont zipties cause the fan to create vibration noise, even the stock retention clip with the rubber mount creates an audible vibration noise with certain fans/speeds

[stealthbomber]

Ultima 90i with 2x 120mm fans push/pull, S-Flex 1900RPM + Yate Loon fan:




Improvements are similar, anything from 2C-5C lower load temps, as mentioned worth the cost even just for the extra security!

[Wily Coyote]

I really don't understand how you get lower temps with two fans. Fans in series generate the same cfm as one fan. So where does the cooling come from?

[Demo]

I really don't understand how you get lower temps with two fans. Fans in series generate the same cfm as one fan. So where does the cooling come from?

More static pressure perhaps???

[Wily Coyote]

Maybe. But static pressure becomes less a factor in the relatively open environment of a pc case. You guessing? I am.

[yenniedn]

I really hate the ugliness of the new TRUE LGA1366 fan shroud . . . I have the "old" TRUE 120 that I got the LGA1366 bolt thru kit for and use two sets of wire clips for my push/pull setup.

[OS-Wiz]

I really hate the ugliness of the new TRUE LGA1366 fan shroud . . . I have the "old" TRUE 120 that I got the LGA1366 bolt thru kit for and use two sets of wire clips for my push/pull setup.

You can hate it all you want, but it sure makes mounting the fan easier

[Baron_Davis]

i've got lapped TRUE + lapped e8500 (C0) + 4 S-Flex F's (2 push + 2 pull, zip tied, looks very neat). My cpu is overclocked to 4.0 on 1.34V (I took it a lot higher but not worth it for the extra 3-500 MHz imo.

Orthos stable for hours...get around 50 load with Orthos.

[Demo]

having 3 more fans and getting 500Mhz is pretty good imo considering the noise is tolerable.

[CedricFP]

I really don't understand how you get lower temps with two fans. Fans in series generate the same cfm as one fan. So where does the cooling come from?

It's pretty common knowlege, at least with radiators in WC. I'm not exactly sure of why it is the case, but I suspect that fans in series only generate the same CFM when there is no restriction. In this case, putting a heatsink or radiator in between the 2 fans, you are bound to lose airflow.

PS. I'm just guessing

[yenniedn]

You can hate it all you want, but it sure makes mounting the fan easier

That's good . . . it's still ugly

[OS-Wiz]

That's good . . . it's still ugly

Agreed, what color to you want me to paint it

[OS-Wiz]

OK, my guess on why two fans work better, albeit, just a couple degrees. The pushing fan looses its force fairly rapidily going thru the fins. The pulling fan helps pull the air thru a little faster. All I know is that my testing on my TRUE indicated a 1-2c idle and 2-3c load temp improvement using two fans. I tried two fans on my non-extreme TRU and it didn't help, but didn't hurt temps tho What I like best about using two fans, even when it doesn't help, is that you have a backup fan, should one fail.

[Wily Coyote]

OS~ I certainly don't disagree with your results, but at the same time I still don't understand why. Your guess makes as much sense as anything else I've heard. But why wouldn't it work on another hs? I've tried every conceivable combination of fans on my IFX14. And since it has two sets of fins, that's a lot of combinations.

My last test was to put a solid lexan divider in the middle and a fan on the outside of each set of fins. One blowing to the rear exhaust, the other blowing toward the front of the case with a large cfm case fan exhausting out the side. No improvement. At least nothing significant.

The only thing I haven't tried, and may be about to, is to shroud the sides of the fins w/ lexan and try two fans in push-pull. Since fans don't move air in a nice cylindrical pattern, but rather in a conical pattern due to the central hub, maybe by constricting the air pattern I can get a better flow rate through the fins. Will let you know.

[Baron_Davis]

having 3 more fans and getting 500Mhz is pretty good imo considering the noise is tolerable.

yeah tbh it's not that it's not worth it once I get it, it's just a pain to go that route because I become obsessive and waste nights away tweaking everything to perfection. I'll probably do it again, and go for broke...1.5V+

Oh, and just to let you know, because I have 4 fans on the TRUE, 2 of them are actually running at 1700RPM instead of 1600. The bottom fans are making the top fans speed up and they actually make a much louder and higher pitched noise than usual.

[bomberboysk]

I really don't understand how you get lower temps with two fans. Fans in series generate the same cfm as one fan. So where does the cooling come from?

I think its because the sides are not enclose, and air can go out there, using two fans the air is first pushed through the heatsink, and on the other side the fan acts like a vacuum pulling that air out increasing effeciency. Thats my theory on it

[Demo]

I think its because the sides are not enclose, and air can go out there, using two fans the air is first pushed through the heatsink, and on the other side the fan acts like a vacuum pulling that air out increasing effeciency. Thats my theory on it

Im not sure about that but i tried blocking the sides with an illustration board and i didnt get any better temps.

[Navig]

Hi!

If you want some exhaustive fan testing, check out my

Thermalright Ultra Copper review.


or my


IFX-14 review.



As you can see multiple fans in push-pull can significantly help temps, especially when using low pressure 25mm thick fans--altho all my testing was done on an open bench. Enclosed cases, lots of other factors prevail, predominantly hi internal ambient temps.


In any case, fan specs are generated against no back pressure. Hi density heatsinks like the Thermalright Ultra 120 series generate huge back pressures. It's easy to demonstrate. With your fan pushing air thru the heatsink put your hand above the fan. You can actually feel the air being pushed backwards out the front of the fan!

This can translate to pretty straightforward performance differences. For example, in my Copper review, I used 2 120mm Yate Loon fans with very similar specs regarding cfm, rpm, and dB--but one was 25mm thick and one was 38mm thick. The 38mm thick fan produces much stronger pressures--and so performed significantly better than the 25mm thick fan.

navig

[Demo]

After some testing, adding a 1,800 RPM fan ( another Zalman F3 ) reduced temps by 2-3c depending on the heatload.. having 2x F3's at "silent" does not beat a single F3 at 12v (duh)

[LedHed]

I can understand why anyone would want to mount fans on the outside of a heat sink when you have designs like the Tuniq Tower 120 which are much more efficient in space and temperature.



I never load above 49C (even after 11 hours of Orthos Beta) and I also don't have to take up a huge amount of space for the exact same design (120mm fan inside HS)

[dr4gon777]

Noob question: for push-pull, is the airflow of both fans moving in the same direction?

[illidan]

true