What is the best design for airflow?

Hardware Hub Cooling
1

I've tried several searches and it seems I can't find a straight answer to this question: What is the best design for airflow?

The room I'm running this in has ambient temps up to about 30 Celsius, around 25 when the a/c is on.

Now, I have here a mid tower case with four 120mm Corsair Air Series SP fans rated at up to 2300RPM,  1 rear, 2 top, 1 side, a  Cooler Master fan for the heat sink up to 2000 RPM, and a fixed RPM fan at 1100 RPM on the front. Currently I have the side as intake blowing across the GPU and the front as intake.

Idle system temps are CPU: 40, Vcore: 38, GPU: 50 with the a/c off and fans at about 900 RPM, GPU fan at 1700 RPM. GPU runs at full clock because I have an extended display with different a resolution on a gtx560ti.

Load system temps are typically up to CPU: 67, Vcore: 52, GPU: 70 with the a/c off running games with the fans at about 1800RPM, GPU fan at 3000 RPM. I could easily push for 2200 RPM on the Corsair fans, but I want to keep the noise down.

For the GPU, does it make sense to have a side fan doing that, blowing directly onto the side? Its a single fan GPU with an open design, so it blows hot air off the GPU in every direction. I just don't want contradiction where air is leaving the vent at the very top of the card and the side fan is blowing it back in.

Does it make sense to always have the top fans as exhaust because of the logic that hot air rises, or do I want to point them downward blowing across my Vcore and having the back as the only exhaust?

Also if I have a top fan blowing upward away from my RAM and the CPU fan blowing through the heat sink from the RAM side, would that perpendicular airflow be contradictive? Do I want more air passing through the heat sink or do I want more air leaving the case?

Also, the motherboard I have is an Asus Sabertooth P67 with the plastic thermal shroud thingy. At first I had a 50mm assist fan to circulate air underneath the shroud, but then I realized that fan is right above the GPU so its drawing in hot air. This bothered me so I disabled the assist fan but that made the overall temp 2 degrees warmer. So instead of putting the assist fan back in, I opted for taking the plastic shroud completely off and replaced the 50mm assist fan with one of the Corsair fans mounted on the side panel that basically serves the same purpose. Am I better off like this or should I put the shroud back on with the assist fan? It cooled the GPU rather nicely, but not any noticeable change on the motherboard itself though.

One more thing. what temps should I pay more attention to on the motherboard. Running Asus Suite II, I get probes for Vcore, DRAM, VCCIO, VCCSA, PCIE, PCIE, USB3.0, and SATA. I'm aiming for keeping the CPU under 55,  Vcore under 45, and everything else under 40 in an air conditioned room. 

One more, more thing. What average temp should my PSU be running at? The surface felt way hotter to the touch than the air being blown off my GPU while running a game. I would, but I don't have a way to measure its temp using numeric accuracy. 

 

 

2

Convection doesn't really matter in pc cases.They are small and have fans directing the air.

The general idea is you make a side the intake and the opposite side the exhaust so the air flows in one direction.

Your currnet config matches that.

Dont worry about psu or motherboard temps.Those things are designed to run hot.

3

Your temps dont look too bad. But if you still want to improve temps you should make sure that the arangement of your fans creates a directed airflow. like front/bottom to top/back. that it much more important than the number of fans.

If you are using dust fliters make sure you still have a positiv air pressure in the case. if your exhaust fans are fighting each other for air, they will draw dusty air from every little crack in your case.

also i am not familiar with your fans you are using. I personally use high static pressure fans and have fantastic results. especially with rads or filters.

I also haven't seen you mentioning your cpu cooler. stock coolers suck, i dont know any exception. there are great coolers out there that will cool cpus nearly passivly.

get rid of any restrictions of airflow like cablejunk, helps alot too.

4

your current setup is fine but if you want to try to cool your GPU sacraficing some cooling for your CPU, Make the side fan an outake. There is no set way of cooling a system. Basicly heat rises, so outakes usually higher than intakes and positive static preasure is highly wanted. The higher preasure in your case, the more efficient the heat will be removed from your componants. But of cause not enough outakes and your system will warm up.

Just play around. Find whats best you your system. Very few systems are the same and if you want the best cooling for your system, You have to work it out yourself.

5

I'm using static pressure fans also. Everything going in and out of the case is static pressure, the heat sink is a cooler master hyper 212 evo, and I also have cables routed through the back. I have nothing hanging in front of the heat sink fan, back fan, or the side fan.

6

I tried using the side as exhaust for the GPU and after a 30 minute test it ran about 3 degrees warmer than with no side fan at all. I think having the side as exhaust was stealing static pressure from the GPU fan because the side fan is mounted with the top of it parallel to the back of the GPU. I would raise the side fan higher, but the heat sink is in the way.

7

The cpu cooler looks big enough. check if it is mounted correctly, and/or remount it with high quality thermal compound. thats the only low cost option i can think of right now.

If thats doesnt help, an all in one watercooling would for sure perform better on the cpu and also drops the temperature inside of your case a little, which would help your gpu cooling.

From your 6 fans are 2 intake and 3 outtakes. if your gpu cooler has a blowerdesign and if your psu draws ait from the inside of the case, then you have a highly negativ pressure in your case. disable your 2 top fans and ramp up the front intake, and post us your measurements.

8

I think its time to put up a photo of the inside. 

https://lh5.googleusercontent.com/-2UINo1KFIio/U0CEDfTByII/AAAAAAAAlRk/HuD--LluIkE/w782-h587-no/DSCN0847.png

Yes, the psu draws air in from the bottom. No, the gpu is not a blower type. I did the test without the top fans running like you suggested. I couldn't ramp up the front fan though because its a fixed 1100 RPM fan plugged into the psu. I did these tests with the a/c on in the room, all fans running at 100% with the exception for the gpu fan, running Unigine Heaven, Smite in the menu screen, and a HD YouTube video for at least 15 minutes.

 

Idle, no top fans.

https://lh4.googleusercontent.com/-ToynAj0Zxwc/U0Dfqu4w8GI/AAAAAAAAlSw/s-vrI4TSmEQ/w575-h641-no/idle_noTopFan.png 

 

42% - 52% cpu load @ 3.8ghz, no top fans.

https://lh4.googleusercontent.com/-B_jloYoboOY/U0DfqlhwpII/AAAAAAAAlSs/sOUjHjq66T8/w563-h640-no/load_noTopFan.png

 

42% - 52% cpu load @ 3.8ghz with top fans running

https://lh3.googleusercontent.com/-b633hAK58n0/U0DfqQZN1ZI/AAAAAAAAlSo/K6JSwDb5984/w567-h638-no/load_TopFan.png

 

Most of the time I will turn the a/c off because I hate the noise it makes, so that would add about 5 degrees overall. 

Now I wonder, having positive air pressure in the case, does that mean its better to have a stronger air flow going into the case rather than going out?

9

Just to give you some insight. Alot of bladeservers out there have high pressure intakes only. Air has to go out anyway when pushed, and intakes can direct air better, especially something like the airpenetrators from silverstone.

but in your case, since it has a very open design, i dont see much you can do anymore, except installing bigger coolers with more surface area, with high quality thermal paste.

But dont give up with trying different setups. there is no "one size fits all" when cooling :)

10

I see what you mean. That is something to consider next time I buy a case. 

11

One more thing. Would you say that in its current state that this case has positive or negative pressure? 

12

i'd bet highly negativ.

Pressure is just one aspect when air cooling (but in my eyes an important one). Total air displacement is also very important. that is where open designs come in handy.

here is a very detailed review with your cooler against some other high end air coolers, like the prolimatech super mega. When cooling, size really matters ;D

http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/36597-prolimatech-super-mega-cpu-cooler-review-8.html

13

Sorry for constantly bringing this back up.

The cpu itself is fine. It never peaks over 70 with no a/c in the room running games. Its the rest of the board I'm trying to cool off because of the gpu. Most of the time I get 50 average on probes near the bottom like USB3.0-1 currently = 56 and SATA6G currently = 50 when the cpu and the vrm is hanging around 40. 

I put a high er rpm fan on the front and pointed the top fans downward, so I have 3 intake and 1 exhaust. This does work brilliantly when I have the bedroom a/c on, but not so much when its off. The temps I just listed above were recorded about 30 minutes after I turned the a/c off just running basic things. I honestly cannot determine if positive pressure is actually better for cooling without aided a/c. On negative the cpu, vcore, and vrm hangs around 41 and every thing near the gpu hangs around 45 - 50. On positive pressure same results except everything near the gpu is hanging around 55 rather. 

I have no clue what to do with the top fans. I'v even did this thing where I took out the top fan closest to the back fan and make the remaining top fan exhaust, the back fan intake, and the cpu fan blowing towards the front of the case because the heat sink is right in between the top fans. But that didn't show and different results. I'm already guessing its a bad idea to have 1 top fan intake and the other exahust.

Do I just have a poorly designed case? 

This is what I have:
http://diablotek.com/v2.0/index.php?option=com_virtuemart&Itemid=36&category_id=59&flypage=tpflypage.tpl&page=shop.product_details&product_id=97&vmcchk=1&Itemid=36

14

the only way to cool your motherboard better, is by lowering the temperatur inside of the case, by removing the hot air of gpu und cpu completely by watercooling, or even just watercooling the motherboard too.

I am running out of ideas for aircooling.

 

15
 
 

http://www.extremetech.com/extreme/144731-the-wind-tunnel-computer-that-hopes-to-conquer-cancer

 

http://www.totalgeekdom.com/?p=915

 
16

I have found in my situation, having all intakes and only one exaust has the best result for me. In fact it helps keep dust out of my computer. I have to intakes coming from the front one on the side panel blowing on the GPU, one directly on top of my case blowing on my ram, and one last fan on the back exhausting the hot air from my CPU, my power supply is pulling air from outside the case. so I have 4 intakes and 2 exhausts (GPU). my temps constantly run at 35c CPU 25c GPU at idle.

 

that's my 2 cents. 

17

https://lh6.googleusercontent.com/-UPd0XxAJusk/U0YjUcz_YSI/AAAAAAAAlWk/CVSQMkzC8m4/w207-h441-no/Untitled-1.png


Alrighty, here's my final result that I will settle with. For the Diablo Tek Evo  I have the front as intake, 1 side fan as intake for the gpu, 2 top fans as intake for the RAM and CPU mosfets/VRM, and the back fan as exhaust. 

These temps are at idle with the a/c turned on in the room. My problem was before that the CPU and VCORE temps would rise over 45 at idle which really bothered me. The fan positions I learned  was only half the problem. The other half of my problem was that I just need to turn on the bloody a/c in the room when my system gets too toasty.