[bluezero5]

Just want to get some second opinion.

I have a H80 cooler.

which has a PuLL -> RAD -> Push Fan configuration.

statis temps around 86'C on stress.

I been experimenting with an extra fan, making it:

Pull -> Pull -> Rad -> Push

and temps came off by around 1'C...

on that logic, I wonder..

if I go : Pull -> Pull -> Rad -> Push -> Push

will it be able to drop the temp any further?

[Cigarsmoker]

Only way to know is to try it. At some point though the volume of air passing over the heatsink do not matter. The heatsink can only conduct heat at a certain rate. I suspect you'll get 2-3 deg temp benefit at best.

[thideras]

Unless the fan are specifically designed to be run next to each other (i.e. counter rotating blades, etc), you are only creating more noise. Just run two fans in a push/pull configuration. I'm pretty sure there are quite a few threads here that discuss this exact topic and explain exactly why it doesn't work.

[muddocktor]

^^^^^

What he said.

I have actually done some testing on this myself and like Thiddy said, you will just be making more noise unless you can find fans that turn in opposite directions. And since the only fans that turn in opposite direction from most normal 7-9 blade case fans are server fans generally made by Delta or Nidec, you have plenty of noise with them too.

[Cojac92]

Rather than adding fans. Try changing fans... What fans are you currently using?

[mjw21a]

Check out some Sanyo Denki San Ace fans. I picked up one of those monsters which will output 260CFM full bore but will also spin as low as 500RPM so it can be run quietly too. I believe they also make a 300CFM monster.

[bluezero5]

today I learned that Fan in Series CLEARLY improve the air flow.

by adding one more fan in my pull -> rad -> push config, I lowered the temp by 1-2 'C
(and that's my spare fan.. kinda a P.O.S.)

I plan to buy a good fan and add to it.
hopefully I can drop by 3-4 'C. then I can try to challenge a higher clock.

[thideras]

Correlation does not mean causation. You could have lower ambient temps or different load, for example. A couple hours can easily equate to 1c difference in the room, which would mean a ~1c difference in CPU temps. If everything was exactly the same, I'm guessing that it is increasing the turbulence, which is making the deadspot in front of the fan smaller or causing more air to hit the fins directly. Two fans in series will not ever increase air flow, it can increase pressure if done right (which yours is not).

[mjw21a]

Both Thid and Mudd know what they're talking about. I've been on here for years and generally listen whenever they have something to say. By all means experiment, though I've never really seen either wrong about something. I believe you're better off just going to better fans myself.

[bluezero5]

http://www.achrnews.com/articles/mul...s-and-parallel

a more technical piece on Fans in series and parallel.
mostly:

Two fans in series are normally rated as a single unit in order for AMCA rating definitions and practices to apply. To simplify selection and control, two fans of the same size are typically used with the required flow rate defined by the inlet conditions of the first fan. The combined total pressure across both fans will be the sum of the individual total pressure of each fan. Total pressures are used instead of static pressure because the fans can actually be different sizes and a change in fan or connecting duct areas has an influence upon static pressure values.

[thideras]

That is exactly what I said.

Putting fans in series will increase pressure. It will not increase air flow. But again, since the fans you are bolting together are not not made to be bolted together, it isn't going to do anything but create more noise. You need counter-rotating fans that are precisely spaced to do it effectively, you have neither.

[bluezero5]

no. i wasn't disagreeing, just pointing out that the increase of pressure (not flow) in fact did assist. This might be due to the increased pressure meant the same flow hits the rads, seeping into deeper cracks, or whatnot..

regardless though, I went 2 fans, 1 fan, 2 fans, 1 fan and again.

result was consistent.. 2 fans lower temp under same load.
of course, ideally.. if I have a means to increase the air flow.. all the better...

[thideras]

Ok, that makes a lot more sense.

With the numbers that you are seeing (1c), the increase in noise probably isn't worth it. You'd be better off getting 38m thick fans for the increased pressure. It will be quieter and you will see the same (if not better) temps, compared to what you have now.

[bluezero5]

i am considering that..
the only toss up is not new fans might now be compatible with Corsair H80 fan controller, which is plugged directly to the CPU top.

would it work if I just by pass it completely?
I am worried the pump would stop working if the fans aren't compatible..

[thideras]

I don't know for sure, but going into a panic mode because the fans aren't connected seems a bit silly. I'm guessing they are there for convenience, but I would test this before I bought anything.

[johan851]

It shouldn't cause any problems to unplug the fans from the controller for a moment while things are running. If the pump does stop, just plug them back in. If you're worried, then make sure the CPU is at idle before trying it. You shouldn't have any trouble even if the pump stops for a few seconds.

[mjw21a]

Originally Posted by bluezero5

i am considering that..
the only toss up is not new fans might now be compatible with Corsair H80 fan controller, which is plugged directly to the CPU top.

would it work if I just by pass it completely?
I am worried the pump would stop working if the fans aren't compatible..

Not really an issue. The controller in the H80 and H100 are PWM based controllers. A number of more powerful fans on the market use molex connectors to plug straight into the PSU for power, yet have a separate connector to be used to fan speed control. I'd suggest looking into something like that.

As always I like the Sanyo Denki San Ace series though you may have an easier time coming by some of the higher end Scythe Gentle Typhoons, these can be modded to be PWM fans without much trouble.