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Best fan setup in a Fractal Design Define R4?

gseyffert

76 months ago

So currently this is the fan setup I have going -

Front mounted H100i as intake (all HDD cages in front of it have been removed)

Two 140mm Fractal Design fans on top as intake

One 120mm fan on the bottom as intake

PSU fan facing UP (i.e. pulling air from the case; effectively an exhaust fan). I have a PC & Power Cooling 750W Silencer MKIII

EVGA 760 Blower style GPU (http://pcpartpicker.com/part/evga-video-card-02gp42760kr), of which I will be adding a second one in a month or two.

So my question is, with two GPUs (one for now) and a PSU on exhaust duty, an AIO water cooler, and no HDDs, do I even need exhaust fans? I feel like I don't, and with 3 120mm fans pointing directly at my GPUs, they should be getting enough air. Suggestions are very warmly welcomed.

Comments

  • 76 months ago
  • 0 points

You can't push new air in if you aren't exhausting old air. You were fairly specific in describing where the intakes were and mentioned little about exhaust. You also haven't told us the CFM on any of the fans.

Is the PSU top or bottom mounted?

Your EVGA 760 is just blowing air around the card. There's enough air leakage in that cover that it can't be considered intake or exhaust.

What case are you using? What CPU, and is it overclocked? Is the case side vented? One side or two? Sounds like the top vent is all fans, so no exhaust there. Any un-fanned vents on the front, back or bottom?

It sounds to me that with all of that intake you need a very powerful (and loud) exhaust fan. Exhaust CFM MUST match or be less than 5% higher. Intake should never exceed exhaust or you create stall. My guess is that air is leaving the case out of every seam and rivet hole and there's still positive pressure inside the case.

If the situation were reversed, you'd be sucking air in through those same holes and it wouldn't be directed where you want it, nor would there be any filtering to keep out dust.

You need the H100i fan. If you run intake on the top fans, both have to be there. Top mounted intakes are ineffectual if they don't fill the whole vent area. Otherwise airflow and pressure within the case push a percentage of your intake right back out the opening next to it. This isn't a problem with top mounted exhaust. In fact, if your PSU is top mounted, it's probably already pushing a lot of your top intake back out. I don't think you need the bottom fan as intake, and it would be problematic as exhaust because hot air rises.

Without having seen this setup or measured the flow, I would advise a bottom exhaust fan with high CFM to suck air down, and a less powerful rear fan for the sake of noise. If it were my setup, both those top fans would be slow moving exhausts and I'd be drawing only from the front and bottom. And if you have any side vents, all of this goes out the window because I didn't factor those into the airstream.

  • 76 months ago
  • 1 point

As mentioned in the title, it's a Fractal Design R4 with a windowed side panel (no fan mount on either side panels). The rear fan mount is covered. PSU is mounted on the bottom.

Well it would be a simple matter for me to flip the top fans around and use them as exhaust. The top fan are hooked up to the fan controller in the case, and I could put them on the 5V setting and have my H100i as intake in the front of the case, as well as the bottom mounted 120mm fan. That would give me 77 CFM from the H100i, and 74 CFM from the bottom fan (listed here - http://pcpartpicker.com/part/arctic-cooling-case-fan-afaco12000gba01), so 151 CFM intake. My top fans are 66 CFM max (the stock Fractal Design 140mm fans), which would give me 132 CFM as exhaust, plus my PSU and GPU. You think that would be a better setup? Also, what temperature would be best to measure to determine which airflow setup is working the best?

Also, I have a 4770k OC'd to 4.3 GHz, but it's under the water cooler so it's not pushing a ton of hot air around.

  • 76 months ago
  • 2 points

Sorry, I began pondering the problem and forgot which thread I was in and didn't remember the thread title. Had I been paying attention, it would have answered several of my questions.

First, you need to decide if there is actually a problem. The problem with a lot of engineering solutions is that they're based on theory and nobody actually looks to see what it is they're trying to solve. The question is, what temperatures do you have right now, and are they too hot? I feel that a lot of people just throw fans at a problem without analysing what temperatures are and where the breeze is going. In my opinion, too many fans blowing form too many directions only create miniature tornadoes with dead air right next to them.

While having more intake than exhaust is not what we want, I believe that 151 in/132 out would be better. That's about 12.5% difference. You're right that between the GPU and PSU it should match them even closer. No need to mess with the PSU fan. I'm not sure it could even be flipped.

Measuring temps might be problematic. To be honest, I had always used thermocouple wires hooked up to an electrical multimeter. You know what a multimeter is? Measures ohms, volts, amps.

As a first tool, and least expensive, take a look at HWMonitor. www.cpuid.com/softwares/hwmonitor.html? It's freeware and gives you a bunch of temperatures from the fans, CPU, video and hard drives (which you don't have in this case). There are probably many programs like this, I don't see how one could be better than another because they all get their data from the same places.

Ideally, the next step would be to find someone with a multimeter, because thermocouple wires are thin enough to fit through various holes in the case and can be attached to specific areas around the case that you want to measure. Find out if the owner of the meter knows how to work with thermocouples, it used to be standard practice in electronics courses. You tape them down, run them out of the case, hook up the meter, then turn the machine on. With ten-fifteen feet of wire, you could set up the box with several monitoring points, and move the meter from one set of wires to another. RadioShack used to sell cheap digital multimeters for less than $10 but now I see the cheapest is $25. Thermocouple wire can be bought from McMaster-Carr for less than $1.50 a foot. http://www.mcmaster.com/?m=true#thermocouple-wire/=o8wr8k I think Type J is what you want here but I'm not certain I remember anymore.

Possibly easier to get is a pyrometer, which is essentially the same idea, measures temperature. The common ones that you see are infrared thermometers (optical pyrometers) for about $30. They're light guns that you need to point at things. This is hard when the things are inside a solid case and it's difficult to aim through fan holes and windows. It reflects off plastic windows unless done in a dark room with the unit right up against it. You can never be sure where the thing is pointed and how wide of an area it's measuring. Newegg sells these, I don't know how anyone can use them on computers. Nobody I know ever trusted the accuracy of an infrared thermometer, but we may have all been snobs. There are also probe pyrometers, similar to thermocouples and a meter. These generally have thicker wires and larger, heavier tips than thermocouple wire, making them more difficult to use. You may not (probably not) be able to fit the ends of the wires through the various openings in the case. There is only one set of leads, so you have to measure things one at a time. Since the ends of the leads are bigger and heavier, it can be hard to position them and secure them in place. Some are smaller than others. Your best lead for a pyrometer is an auto racer or hobbyist. They use them to get tire temperatures. Hobbyist pottery makers, glass blowers and metal figurine casters also use pyrometers put I don't know that they would be accurate at the low end of the range where computers operate. Newegg also sells pyrometer probes in their automobile section but those are for exhaust temperatures. Not what you want and expensive. At one time I knew how to build a pyrometer with an $8 RadioShack multimeter and a few resistors but I've forgotten. The internet has everything though, so the plans are probably out there. Here's a homebuilt setup that cost $56. http://www.angelfire.com/tx5/hite/thermo/thermo.htm

Your fans probably have a thermocouple wire and monitor circuit built into them. That's how they know when to change the rpm.

  • 76 months ago
  • 1 point

Haha yes, I know what a multimeter is... I was thinking I'd probably run the benchmark for a game like Metro 2033 maxed out to stress as many components as possible, observe the temperatures on my second screen, then move some fans around and see if the temperatures drop much. I have a multimeter at home, but not up here at school.

My temps as they are are generally fine. But I'm a little concerned about adding the second 760 and it getting enough air. I think airflow will become more crucial then. Right now, I live in a pretty cool area (the Bay Area), so I think some of my current temperatures are due in large part to that, though I would like to see my GPU stay a little cooler than it currently gets.

  • 76 months ago
  • 2 points

Cool. I usually explain things to people thinking they know nothing until I find out otherwise. If you throw too many confusing things at folks they tend to only ask about half of what they didn't understand and guess on the rest. Then the project fails and they blame me. If we were speaking in person all of these things could be worked out as I went along, but the internet, you know.

I'd worry about heat soak if you taxed the system then stopped and moved the fans. You need a cooling period between tests, I expect an hour would be fine. Naturally, you'll want to keep the environmental conditions about the same, but with modern home heating/cooling that won't be a problem. You're right about the Bay Area being a moderate environment. Coldest place I've ever spent 4th of July was San Francisco.

What are you using to monitor temps? Software is notoriously inaccurate but since you're comparing apples to apples it doesn't matter.

  • 76 months ago
  • 1 point

Haha no worries man. I feel you. And yeah, it gets pretty chilly up here...

I am using software. It seems to be better even at idle with the top fans on exhaust though. I've gotten CPU readings as low as 23C, which is a new record. Even seeing my GPU dip to 29 lol. I think it'll be better for airflow anyway to have the air moving across the motherboard then out the top.

  • 76 months ago
  • 1 point

Also, my PSU has a 140mm fan, and I really don't want to go through the trouble of flipping it around if at all possible...

  • 76 months ago
  • 1 point

PSU faced down exhausting heat is generally the best. You don't want your PSU to blow heat into your case. you definitely don't want that if you are running SLI cards because it will blow hot air straight into your bottom card.

  • 76 months ago
  • 0 points

Just fill up the fan spots... 3 intake and 3 outtake

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