Corsair Air 540 - Front intake fans 2x140 vs 3x120

evsknight · 21 Jul 2015 at 12:30

Afternoon,

I've got the above and currently have 2 x bequiet! pure wings 2 fans which are intake and 1 as an exhaust on the back. (running at 750rpm each)

I'm not really noticing any problems with heat build up in the case at the moment that I'm aware of - I've got 2 x 140mm Corsair SP140's in push for exhausting air out over a Corsair Hydro H100i which is cooling the CPU.

I've got an MSI 980ti running in there and under load the graphics card doesnt go above 74 degrees. It's about 21 ambient in here so doesn't seem too bad really?

When I had an R290x it was different and the case did get warm with the GPU hitting 76/77.

As I've not had a really hot day in blighty yet with this new 980 and I may do some overclocking of it soon I'm looking for advice on improving the airflow.

So my question boils down to whether 3 x 120 SP's would be a noticeable improvement on intake/airflow and also if it's a big jump in noise as well.

I keep reading good things about Noctua but I'm a little worried about buying 70 quid's worth of fans for little change.

TIA

clone · 22 Jul 2015 at 10:34

I would go with the 2 140mm I've got 2 in my case in sig and I'm more than happy with them as they give good airflow,just make sure you have a filter to keep the dust out.

dacads · 22 Jul 2015 at 11:17

Definitely 2x 140mm, I'm assuming that's what you have now with the be quiet fans?

FredFlint · 22 Jul 2015 at 22:45

I use 2*140mm fans.

andy_mk3 · 22 Jul 2015 at 22:48

I run 3x120mm, mainly cos it's more OCD friendly to me lol. Airflow is plenty for my 2600k and 2x 280x's

JediFragger · 22 Jul 2015 at 23:33

I switched from 2x140mm to 3x120mm and it def helped me with SLi temps (mainly because the bottom 120mm points towards the middle of my cards). I think their's a combination that's suits your system imo.

doyll · 23 Jul 2015 at 12:08

What JediFragger said.
3x 120mm fans move similar air to 2x 140mm fans of same design. But the flow pattern of air from fan to component is the key to good case airflow and cooling .. That and how well the components heated exhaust flow out of case .. hopefully without contaminating the cool intake air.

Here's a simple guide to optimizing case airflow
http://forums.overclockers.co.uk/showpost.php?p=26159770&postcount=7

evsknight · 23 Jul 2015 at 13:52

@clone - Yup the case has a dust filter in front and a mesh grill. It's why I'm potentially leaning to SP fans as I think these bequiet ones are just AF fans.

@dacads - Yes that's the ones. They do the job but it was for future airflow improvement if I start to OC the 980ti

Currently the lower 140mm is square on with the 980Ti - so the middle is pretty much lined up with the end of the card and about a 3 inch air gap between the fan and the card so probably helps directly cooling the card but below the fan there's a good 3 inch gap of fan filter only so was wondering if that would pull case air back through from underneath

doyll · 23 Jul 2015 at 14:37

Sorry to say, the only thing going for AF and SP fans is their beauty ring. They are higher prices, noisier and move less air then many others. I would consider using something like the EK Vardar F3 using PWM signal control from CPU fan header and/or GPU fan header. This means fans cycle with component demand/s .. running much quieter and only speeding up when component fans do.

Here's a guide to setting up PWM control on case fans.
http://forums.overclockers.co.uk/showpost.php?p=26079729&postcount=5

dacads · 23 Jul 2015 at 14:44

Well in general terms 3x120mm fans should be theoretically louder, but if you go with the right ones you won't notice much difference.

There's definitely potential to buy better 140mm fans or 3x 120mm fans that will move a bit more air.

ttaskmaster · 23 Jul 2015 at 15:20

evsknight said:
So my question boils down to whether 3 x 120 SP's would be a noticeable improvement on intake/airflow and also if it's a big jump in noise as well.

SPs would be noisier.
AF fans would probably be better, anyway, but there are better fans for airflow than Corsair.

evsknight said:
I keep reading good things about Noctua but I'm a little worried about buying 70 quid's worth of fans for little change.

I was in the same position last year.
I went for it and dropped about £140 on Noctua fans - Not regreted it in slightest!

doyll · 23 Jul 2015 at 15:52

dacads said:
Well in general terms 3x120mm fans should be theoretically louder, but if you go with the right ones you won't notice much difference.

There's definitely potential to buy better 140mm fans or 3x 120mm fans that will move a bit more air.

Depends on fan speed. Often 140mm fans are lower speed an lower noise. To me what is more important is the path the airflow takes inside of case .. and without trying both ways there is no way of knowing which will give best performance.

ttaskmaster said:
SPs would be noisier.
AF fans would probably be better, anyway, but there are better fans for airflow than Corsair.

I was in the same position last year.
I went for it and dropped about £140 on Noctua fans - Not regreted it in slightest!

I would go with higher pressure rated fans. Reasoning is lower speeds mean lower airflow and pressure .. and with filters & grills restricting airflow having more ability to overcome the resistance at low rpm is advantages.

I like comparing airflow and pressure to horsepower and torque in cars. Having lots of horsepower and low torque make for a unmanageable vehicle. Look at how easily race cars can stall trying to get moving. But a lower horsepower high torque engine .. like diesel engines they will pull out with almost no effort at all.
Static pressure and airflow is similar. If we have 2 fans both rated 80cfm with fan A having 1.0mmH2O and fan B having 2.0mmH2O with grill and filters in front of them with a resistance of 0.5mmH2O fan A will be flowing 40cfm and fan B will be flowing 60cfm .. but increase this resistance to 1.0mmH2O, fan A will be flowing no air while fan B will still be flowing 40cfm.

Edit: Don't believe the actual cfm figures. I only used them to demonstrate how airflow and pressure ratings apply to our use of fans. We never use fans at there static pressure rating .. because they move no air. We also rarely use them with no resistance (unless it's in hot weather and we set one on our desk for airflow on us) because there is always something in the case restricting the airflow to and/or from the fan.

evsknight · 23 Jul 2015 at 15:59

Thanks, so going for some decent Noctua's or EK Vardar and setting them in a PWM format would be better for airflow and noise then.

Unfortunately my motherboard only has 1 PWM header which I use to control 2 x Corsair SP140's on the CPU radiator so that would be the 'master' fan in a larger PWM setup, is it ok to have both 140's and 120's on the same PWM loop or would the speeds get out of whack so I'd need two loops?
Or just replace the 140's in the front with other 140's and PWM all 5 fans together?

ttaskmaster · 23 Jul 2015 at 16:35

doyll said:
I would go with higher pressure rated fans. Reasoning is lower speeds mean lower airflow and pressure .. and with filters & grills restricting airflow having more ability to overcome the resistance at low rpm is advantages.

Higher pressure also means higher noise created by the air passing through the restriction(s) too, though.
This is the main reason to try airflow fans on radiators - I know a couple who have very good results from doing this, though it's not something I've done much of myself, yet. The noise/performance issue won't be a factor for me until I switch from this NOISY all-in-one to proper watercooling, heh heh!

Depends on how restrictive the restrictions are.

evsknight said:
Thanks, so going for some decent Noctua's or EK Vardar and setting them in a PWM format would be better for airflow and noise then.

PWM is just the method of controlling fan speed, or rather having the PC adjust it for you depending on what it's doing.
The difference is in whether you use an Airflow or a Static Pressure fan (or indeed something between the two) and in where you place it, as well as what internal components the airflows have to blow around inside the case.

The difference (120mm, anyway), as an example: http://www.noctua.at/main.php?show=which_fan_is_right_for_me&lng=en

I personally dislike PWM, as you can get this constant spin-up/spin-down whizz from some fans, especially if they're designed for high outputs. You can program in automated fan curves and fancy stuff like that, but I'm a simple kid and prefer a fan controller with knobs on!
You're also limited to what each header can supply. You can use a 4-pin fan on a 3-pin header (usually) and still control the fans, you just won't get the full PWM experience.

evsknight · 23 Jul 2015 at 17:31

I meant for having 120mm and 140mm in the same PWM chain - I guess the additional voltage will just spin up the 120's faster if I have a 140 as the master.

I've currently got 2 PWM fans on a PWM header on the rad at the moment, the 3 in the front are just standard controlled off motherboard headers and I've set up cooling curves for them.

The only reason I was looking at static pressure for the front is due to the dust cover and grill from the front of the case, I kept seeing lots of different recommendations of SP in the front where you have things blocking the airflow.

ttaskmaster · 23 Jul 2015 at 18:10

evsknight said:
I meant for having 120mm and 140mm in the same PWM chain - I guess the additional voltage will just spin up the 120's faster if I have a 140 as the master.

Fans shouldn't draw more voltage and so spin faster than their maxiumum, if that's what you mean.
Bear in mind also that 120s will make more noise than 140s, especially at higher speeds.

evsknight said:
The only reason I was looking at static pressure for the front is due to the dust cover and grill from the front of the case, I kept seeing lots of different recommendations of SP in the front where you have things blocking the airflow.

TBH, I'd just try both and see.
If you put SP fans behind my front intakes they'll be very quiet, and yet the very same SPs on the side intakes sound like an F-14 launching off a carrier!!

There is a science to this, but there are so many variables, I find it's easier to just experiment. High end fans can be sold on easily enough if you don't like them.

doyll · 23 Jul 2015 at 18:13

Normally there is no problem running different fans on same PWM signal. Only potential problem is if fans spin too slow or too fast compared to others. The fans speed is based on a percentage of PWM signal and how the PWM PCB is programed and the rpm range of fan. For example the TY-147 and TY-147 are same fan in all respects except for PWM PCB setup. TY-147 is 550-1300rpm and TY-147A is 300-1300rpm

doyll · 23 Jul 2015 at 18:45

ttaskmaster said:
Higher pressure also means higher noise created by the air passing through the restriction(s) too, though.
This is the main reason to try airflow fans on radiators - I know a couple who have very good results from doing this, though it's not something I've done much of myself, yet. The noise/performance issue won't be a factor for me until I switch from this NOISY all-in-one to proper watercooling, heh heh!

Depends on how restrictive the restrictions are.

PWM is just the method of controlling fan speed, or rather having the PC adjust it for you depending on what it's doing.
The difference is in whether you use an Airflow or a Static Pressure fan (or indeed something between the two) and in where you place it, as well as what internal components the airflows have to blow around inside the case.

The difference (120mm, anyway), as an example: http://www.noctua.at/main.php?show=which_fan_is_right_for_me&lng=en

I personally dislike PWM, as you can get this constant spin-up/spin-down whizz from some fans, especially if they're designed for high outputs. You can program in automated fan curves and fancy stuff like that, but I'm a simple kid and prefer a fan controller with knobs on!
You're also limited to what each header can supply. You can use a 4-pin fan on a 3-pin header (usually) and still control the fans, you just won't get the full PWM experience.

What?

Airspeed causes noise, that's a fact.

But the pressure rating of fan make no difference. Just run the fan a a lower speed so there is not grill noise.

Using "airflow" (low pressure) fans instead of higher pressure rated fans makes no sense to me. Some of my fans have more than 3.0mmH2O rating, but when they are running at 400-550rpm they are dead quiet .. with all kinds of reserve airflow just waiting for that once a year scorcher of a day I may be trying for a super OC and need all the airflow I can get.

dislike PWM, as you can get this constant spin-up/spin-down whizz from some fans

Only if you don't have enough sense to adjust the heat to PWM/rpm curve and raise or lower it slightly to solve the problem.

Just because the fans have high pressure & high airflow doesn't mean it has to be used. Same as having a performance car doesn't mean we have to go fast and burn lots of petrol. I get 35-40mpg with my BMW 535is with 4.0 ltr bored and stroked engine, but on the race track I'll get 8-12mpg and wear out a set of new brake pads in a couple of hours track time.

MrMD · 23 Jul 2015 at 19:01

You just have to buy the right fan for your needs

OP

i tried a bunch of different fan configs when i had my 540 aircooled.Your best bet IMO is 3 120mm fans that have good rpm ranges.

Difference between SP/AF is minimal as front intakes.SP orientated fans were slightly louder from my experience compared to AF ones.

3pin/4 pwm it makes little difference.Just as long as you have a way to control their speed,be it through Bios fan curves,a regular fan controller,PCB splitter or even speedfan.

Of all the fans i have messed about with this is the most impressive fan for noise/airflow i have used

YOUR BASKET
1 x Cougar Vortex HDB V12H Fan, 120mm £8.99
Total : £11.27 (includes shipping : £1.90 Ex.VAT).

Very quiet,shifts a lot of air.They are however 3 pin fans.Connected to a motherboard header and controlled via speed fan they can do a range of 300-1200rpm.

ttaskmaster · 24 Jul 2015 at 14:45

doyll said:
What? Airspeed causes noise, that's a fact. But the pressure rating of fan make no difference. Just run the fan a a lower speed so there is not grill noise.

As mentioned, it depends on the nature of the restriction.
Through a Rad, for example, you get a lot of turbulence and half the noise is the airflow bouncing around and collectively reverberating off different surfaces. HDD cages tend to act like baffles in an exhaust silencer, killing the airflow and spoiling all that lovely spread configuration.

I often find the restrictions slow AF fans down a touch, which keeps the noise down a bit, but they still perform... whereas SPs force the air - This gets noisy, so you turn them down, which drops performance, which heats your system, yadda yadda.

If you're having to turn it down because it's 'too noisy', what's the point? You're robbing all the advantages, though I'd suspect a bad choice of fan/mount if it's that problematic... They should all be fine below 1,000rpm.
But this is why some people rip out the meshes and filters - Better performance at lower noise without having to change fans.

doyll said:
Using "airflow" (low pressure) fans instead of higher pressure rated fans makes no sense to me.

SP forces air through restrictions, partly because it's focused flow, but they're designed to just get through that short distance where its restricted.
AF shifts a lot of air, but still has reasonable pressure too.

Case in point: You put SP fans on my side intakes, where there's almost no restriction at all, you will force air through but achieve nothing. You can barely feel it 6" away. You put AFs there, you will blast loads of air in at a decent spread and the whole Mobo will cool very nicely.

doyll said:
when they are running at 400-550rpm they are dead quiet

Most fans are dead quiet from just under 1,000rpm. It's how they perform at that point and below that matters for daily use.

doyll said:
Only if you don't have enough sense to adjust the heat to PWM/rpm curve and raise or lower it slightly to solve the problem.

It's more that the system is being overclocked or otherwise suddenly stressed that causes it. Curve it up all you like, but going from 5% to 80% load will result in spin-ups as the fan meets whatever levels you set it to.
I prefer constant noise (as do the people I'd normally disturb), which is why I retain manual control.

doyll said:
Just because the fans have high pressure & high airflow doesn't mean it has to be used.

No, although it depends on what you need and want.
If you have massively capable fans, I'd reckon you bought them because you needed them.
As is, I get flappy when my system components go above 25ºC, but I came from having a build where they'd near-idle at 44... Maybe I'm just OCD about it now, but I still require things to be as cool as possible, which is why I have decent fans.

doyll said:
Same as having a performance car doesn't mean we have to go fast and burn lots of petrol.

Err... yes it does!!

Well, it does for bikes, anyway. Not sure about cars, but given how I see people drive them I assumed it is mandatory...

doyll said:
I get 35-40mpg with my BMW 535is with 4.0 ltr bored and stroked engine, but on the race track I'll get 8-12mpg and wear out a set of new brake pads in a couple of hours track time.

I actually get better mpg if I go everywhere fast... I get 28-32 normally, but over 50 if I'm doing (ahem) speeds...