Side or top intake fan on Fractal Design R3?

[Ika]

As I'm planning my next CPU build one of the things I'd like to focus on is good air cooling, but without compromising silence. Since I keep my desktop in my bedroom, frequently listen to music on open headphones, and spend a lot of time at my computer, I wanted to keep the noise level as low as possible without also compromising cooling ability or spending too much money. The Fractal R3 is designed for silence so it should be much better than my current Enermax Phoenix.

I've purchased four Scythe Slip Stream SY1225SL12M (1200RPM mediums) to use as my case fans, since they only cost $2 more than some Yates. I have a Hyper 212+ for a CPU cooler, which I think I'll keep the fan stock on and keep PWM on silent or low control. I also picked up a second 3-fan PCI bracket fan controller to use alongside the provided Fractal one (interestingly, it's exactly the same, but branded Xigmatek). Each will control two case fans.

I'm planning to use two intakes on the front, a rear exhaust with CPU fan pointed towards it, and PSU as a pseudo-exhaust. I have one more fan and another intake to fill (for positive pressure). I can put the last Slip Stream on the side, or on the top, in a horizontal position. I would prefer the top but since the SS is a sleeve-bearing fan, I'm afraid it's going to wear out prematurely. But I've also read side fans increase noise a relatively considerable amount. So what should I do?

TL;DR - Have Scythe Slip Streams, need one more intake fan. Should I put the last one on the side panel or on the top?

 

[beginner99]

If have the R2. I guess it depends on placement of your case. I have a top 140mm and it does at considerable to noise (Silentwing). So it might just be because of opening the top exhaust and not the fan itself.

You could also consider the bottom fan position depending on the available space you have there. If you do so it is highly recommended to put a dust filter there on the outside for easy cleaning + not have it standing on the floor directly.

 

[lehtv]

Don't use the PSU as exhaust. It'll only mess up airflow - heat rises, so the air exhausted by the PSU at the bottom is air that could potentially be used for cooling. And since you put intake fans near the bottom, they'll provide positive air pressure that help the hot air to rise. Plus, when put fan down, the PSU will breathe cooler air which will keep it in better condition in the long term.

I've got the Fractal R3, here's how I have it set up (quiet and cools pretty well):

Two front intakes 120mm (silverstone AP121 @ 600RPM).
One floor intake 140mm (sharkoon se800 @ 600RPM).
One rear exhaust 120mm (fractal @ 500RPM).
One rear-top exhaust 140mm (sharkoon se800 @500RPM).
The second top slot open.
Side panel slot blocked for quietness.

I've tested using both top slots as exhausts. Using the second slot did nothing temperature-wise. So I just leave it open with no fan, and hot air can rise out on its own due to positive pressure - if it's not taken out by the exhaust fans. I've also tried using the second top slot as an intake, but all it does is push warm down and increase HDD temperatures (potentially GPU temps too but it was the same for me). CPU temperature wasn't affected.

 

[Ika]

lehtv, you have the PSU fan oriented facing down? I was planning on putting PSU fan-up because someone mentioned his PSU was warmer fan-down, and when placed fan-up it got better. I'm also going to be on a carpeted floor. I'll probably put a piece of leftover MDF underneath the case but there's not a lot I can do about this setup. I'm afraid there isn't going to be enough space on the underside of the case to provide good airflow for the PSU fan.

 

[lehtv]

Someone mentioned? It'd be nice to know how he measured the temperature. That's an interesting finding, would be nice if someone could replicate that... Actually, I could do it some time. I've got a fan controller with some thin temperature sensors that I could attach on the outside of the PSU and measure temperature with the system at load, in both orientations.

But on a carpet floor dust intake may be a bit problematic (though the case does come with a removable filter). The case has feet so it'd be able to breathe even if on a carpet

 

[Ika]

Very anecdotal, but here:
http://hardforum.com/showpost.php?p=1037368795&postcount=52

So my X650 was getting pretty warm/hot so I flipped it upside down so that air is being forced into it from the rest of the case. It's noticeably cooler.

Looks like he has his case on a desk, so carpet is not a problem. If you have the time to do a temp test that would be awesome. In the meantime I'll look around and consider my options.

 

[adlnc08]

Is it better to connect the fans to the motherboard, or use the controller that came with the case? I just have the two that were included for now, but might add another if needed.

Thanks!

 

[Ika]

Is it better to connect the fans to the motherboard, or use the controller that came with the case? I just have the two that were included for now, but might add another if needed.

Thanks!

Motherboard lets you use software monitoring and control (like Speedfan, or whatever your motherboard software is), so that's probably the preferred way. I plan on having four fans, though, and the mobo can only support 3 (4 total, but one for PWM CPU), and I didn't want an odd one out. I figure having PCI bracket fan controllers will help keep the case interior cleaner, as well.

 

[lehtv]

The mobo lets you set a fan profile in the BIOS too (ASUS QFan, silent/normal/performance profiles, dunno about other mobos).

Aflac, you could use fan splitters to connect two fans onto one header. Not sure how PCI bracket fan controllers help keep the interior clean? You can route fan cables behind the motherboard anyway.

 

[Ika]

My PCI bracket controllers come with a 3-way splitter (control 3 fans from one controller) so that would allow all the fan cables to be in the same place, as opposed to on the top left, top right, and bottom right of the motherboard (as on mine). Didn't know I could do splitters for the motherboard headers, though. I'll play around with them.

But in any case... this topic seems to have gotten way off-topic. My original question still needs to be answered!

 

[lehtv]

I thought I answered that in my first reply

I've tested using both top slots as exhausts. Using the second slot did nothing temperature-wise. So I just leave it open with no fan, and hot air can rise out on its own due to positive pressure - if it's not taken out by the exhaust fans. I've also tried using the second top slot as an intake, but all it does is push warm down and increase HDD temperatures (potentially GPU temps too but it was the same for me). CPU temperature wasn't affected.

I may not have been very explicit in the conclusion though. So, in conclusion: using the top fan as an intake is counterproductive (unless the airflow is very crap to begin with, which it isn't in your case). Heat rises on its own and as a result of air pressure from the intake fans; all the top intake does is push the heat back down and increase temperatures of your components.

I would recommend you put the intake fan on the floor or the side. You can test either config and see what happens to temps. Leave the unused top slot open so it doesn't block hot air.

BTW I will be done with my PSU testing soon

 

[Ika]

The "heat rises" thing makes more sense in a low-airflow scenario, but when there's two 120mm intake fans going at 15-25cfm, the amount of circulation inside the case will probably make that moot. Heat rises, but not that quickly.

I decided to go fan-up on the PSU, mostly to help my GPU temps, since my GTX460 is known to be a little hotter and louder than most cards. The PSU should help some, at the expense of a slight temp increase at the PSU. Also I don't have to deal with worrying about getting the case off the carpet or problems from the ground being so close the fan, etc etc.

I don't have a way to measure temps besides the motherboard, so if it looks like those temps are accurate enough I will first try two intake, one exhaust + PSU, open forward top, to see what temps and noise level is like. Then I'll try putting a fan in as intake on the top, then closing top and opening side, then putting fan on side. Hopefully I have enough time to do all this

 

[adlnc08]

I'll ask this question here since we are discussing air flow and whatnot with the R3. I'm looking at buying an EVGA GTX 570 to use in this case. There is one model that has three fans, which I think would likely run cooler and be quieter:

http://www.newegg.com/Product/Produc...012-P3-1577-KR

There is a $20 rebate at Amazon, making it $325.

Do you think this design of card would work okay in the R3, or am I better off getting one with a single fan like this:

http://www.newegg.com/Product/Produc...82E16814130622

I'm thinking the 2nd one might exhaust more air out of the case rather than moving it around, but this is just a guess.

Thanks!

 

[lehtv]

The "heat rises" thing makes more sense in a low-airflow scenario, but when there's two 120mm intake fans going at 15-25cfm, the amount of circulation inside the case will probably make that moot. Heat rises, but not that quickly.

One of the points was that heat rises as a result of the air pressure of the intake fans. Your intake fans are near the bottom, and your exhaust fans near the top. The more you have air flow, the faster the air will move from bottom to top; an intake fan on top will only counteract that. This isn't theory, I've tested this.

 

[Ika]

One of the points was that heat rises as a result of the air pressure of the intake fans. Your intake fans are near the bottom, and your exhaust fans near the top. The more you have air flow, the faster the air will move from bottom to top; an intake fan on top will only counteract that. This isn't theory, I've tested this.

You may be right, but another way to think about it is that the top front intake feeds fresh air directly to the RAM and the CPU, which gets ushered out the back by the CPU fan and rear exhaust. The front intakes push air towards the general bottom of the case (where the video card hot air will be), which then gets ushered out by the PSU exhaust. Without a clear panel on the case and some smoke, there's really no way to tell what actually happens inside the case, so this is mainly just guesswork.

 

[lehtv]

A high enough PSU CFM could indeed change the airflow to make the top intake worth it. Looking forward to your results.

BTW here's my PSU test http://forums.anandtech.com/showthread.php?p=32382810