top case fans suck or blow?

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nighowl2000

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hey folks...built myself a new system just before xmas. Got a question about case venting. When I run the prime 95 test my VCore-1 (located just below the 80mm fan on the top left) get super hot at 58 degrees after 20 min according to the sensors on my sabertooth board. Those two top case fans are blowing out. Should I redirect the fans to blow in for the 2 top case fans?

FYI: Vcore2 was at 45C and CPU was around 53C during the 20 min test.
 
1: Need to tidy up that jumble of cables at the bottom right of the picture, that will help airflow from the front of the case. 2: Heat rises, not much sense going against the laws of thermodynamics. 3: 58c for the VRMs over the MOSFET isn't bad, most are rated for 70c or higher before they begin to have issues. If you were -really- concerned, you could get something like the Antec SpotCool and have it (based on picture geometry) under the radiator pointing up towards the top exhaust fan, but since you're not even close to dangerous temps it will add nothing except peace of mind.
 
omg...>_<.. please.. make some cable cleaning on your case... my eyes bleed with that, as the bud above said, first of all try to make a clean case, that mean a little work cable management cuz what can i see from the pictures its that you have LOT of negative air preassure on your case with both top and exhaust and almost no intake from the front and bottom... what could you do its put high airflow fans on the front and bottom of the case (after make some arrangements with the messy wires).. also a side panel fan help a LOT. specially for the radiator wich its the more amount air exhaust on your case..
 
IDK how much cable management he's going to get more than he has with a non modular power supply.
 
Had the same problem for awhile, it was better (cooler) to have them both as exhaust.
 
bstrang6 said:
IDK how much cable management he's going to get more than he has with a non modular power supply.
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I've used in my case first a cooler master 550w PSU non-modular and the cable management was clean (the bad points was the coloured cables, however was all clean) later i've used corsair TX-750, and thermaltake TR2-750.. Both non-modular.. And my case was still clean.. So, a modular PSU is not always necesary to make a clean enviroment into the case... Cable management depend more on the that in the PSU. I have some old pics of my system when used non-modular PSU if u want so see.. :)
 
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You want to have the top fans exhausting air. Like others have mentioned, tidying up the cables can help a bit. It should not be hard to do :).
 
I always go with the top fans being exhaust. Heat rises so I like to have it goo up and right out. But definitely work on the cable management. It can be a really rewarding project to take on. Be sure to post some before and after photos in the rate my cables thread of the case modding section.
 
What CPU are you running? Also, it's core temp, not VCore, VCore would be core voltage. As others side, do some cleaning, you might have a non modular PSU but there is still space behind the mobo tray and in the empty bays to put cables and not all bunched up in the air path.

What two fans are you using on the rad? They look mismatched and that can hurt cooling, it is always best to have them matched. Also, the top fans should be exhaust, and if you want better core temps turn the fans on the rad around as you have them as exhaust and you should have it as intake for best core temps, as it will be taking in cool outside air and not preheated case air, however this can lead to higher GPU temps etc, how much they rise depends on many factors and you will just have to test it and see.
 
So reversed the two top fans so they are sucking air in and I am getting 5 degrees cooler on my CPU and VCORE-1 on idle and at load. I think the problem is that because the computer sits on the floor space in my ikea desk, the fans where not venting out properly ( only 1/2 inch of space between the case and the drawer).

Yes I know my cable management is bad but meh.....

BlueFireIce:

I am runing a AMD FX8350 OC'd@ 4.3ghz with a asus sabertooth 990FX rev 2 board and they call it Vcore-1 (heat sink to the left of the CPU and Vcore-2 (heat sink directly below the CPU)

The rad is a Antec KUHLER H2O 620 and it only came with one fan so I added a Corsair Air Series SP120 which seems to help a lot after I added it (prime95 CPU temps where going upwards of 65 degrees and vcore-1 was 75+).

Temps where stable after prime95 test for 45 min at 55 degrees for the CPU, 55 for Vcore-1, 45 for Vcore-2
 
Computer should be moved into open air, the fans you moved were the wrong ones, the top fans should be exhaust, not intake. The fans that need to be made intake are the ones on the rad.

What program are you using for stress testing (I assume only Prime) and what for temps? You need core temps, not CPU temp, that is often the socket temp, which means nothing.
 
Ive always ran my top fans as exhaust since heat rises BUT since I got my H100 and its rad is mounted to the top of my 500R, I run the fans on the bottom of the rad as intake. I tried it pushing air out as well as on top pushing air in but on the bottom drawing cool air in, I get as much as 3C cooler temps under OCCT!! Axial fans suck better than they blow so this shouldn't be a surprise I guess. But since youre not running a rad up there, Id keep them pushing the warm air out thru the top.
 
MacLeod said:
Ive always ran my top fans as exhaust since heat rises BUT since I got my H100 and its rad is mounted to the top of my 500R, I run the fans on the bottom of the rad as intake. I tried it pushing air out as well as on top pushing air in but on the bottom drawing cool air in, I get as much as 3C cooler temps under OCCT!! Axial fans suck better than they blow so this shouldn't be a surprise I guess. But since youre not running a rad up there, Id keep them pushing the warm air out thru the top.
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I use a corsair h100i and I would never post the fans of the rad as intake.. in fact it comes with the screws for mount on that way, if you put the h100 as intake then all the hot air will be thrown directly over your RAM and Mobo, also will heat the hoses, pump, and even if your CPU receive a drop of temp, your overall hardware temp will increase in a very noticeable amount.... i have in my case 4 2000RPM 120mm fans as intake on front.. 2xFront of the case and 2xmounted in HDD bays.. i removed the top HDD bay and mounted the top fan over the bottom HHD bay so he receive full fresh aire and throw directly over the both GPUs also part of that cool air go to the top sucked by the fans of the h100i, also I have one fan on bottom of the case as intake and the upper side panel slot as intake and rear slot as exhaust... so most of the heat produced by my VGAs got out of the case by the rear fan, most of the cool air comming from the front go directly to the h100i so always have a cool airflow and i no fck all the airflow inside the case... thats a front to top Airflow.. and work flawless for me.. i prefer to keep all inside my case fresh than just drop few 2-3 degrees on CPU keeping all warm inside...
 
Araxie said:
I use a corsair h100i and I would never post the fans of the rad as intake.. in fact it comes with the screws for mount on that way, if you put the h100 as intake then all the hot air will be thrown directly over your RAM and Mobo, also will heat the hoses, pump, and even if your CPU receive a drop of temp, your overall hardware temp will increase in a very noticeable amount.... i prefer to keep all inside my case fresh than just drop few 2-3 degrees on CPU keeping all warm inside...
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No, I can put my hand under the fans and the air coming in is really no warmer than the outside air and this is while running OCCT. Id rather have the coolest possible air coming in thru the rad than the warmer air inside the case.

Ive got plenty of case fans moving air thru the case not to mention the big 200mm side fan running intake duties. I have no temp issues with any other components. Asus' Thermal Radar shows me temp readings all over the motherboard and they were the same regardless of my top fans running intake or exhaust. The only difference was with the CPU core temp being cooler with the cool outside air being drawn in. I tested it with the fans on the bottom pushing air up thru the fan (exhaust), with them pulling air in (intake), on top pushing air into the case (intake) and pulling air out (exhaust) and with them on the bottom pulling air in was the way that gave the best cooling while running OCCT and monitoring using HWMonitor and Thermal Radar.
 
This isn't a difficult concept, but people are making it out to be.

ComputerSetUp3.png


And pick whichever guide you want to read:
http://www.extremetech.com/computing/128313-extremetechs-guide-to-air-cooling-your-pc
http://www.techpowerup.com/forums/showthread.php?t=42853
http://www.technibble.com/case-cooling-the-physics-of-good-airflow/

And for those that like video:
http://www.youtube.com/watch?v=FRtnuueGaaI

The only time these basic setups should change is if the case has specific placements to be able to compensate for the rear being an intake, meaning the top fans are powerful enough to equalize the pressure so that you don't have an overabundance of positive airflow. With yours having only an 80mm next to and above the radiator, this doesn't apply to you, but here is another video showing how this would work.
http://www.youtube.com/watch?v=O5f7upaIy1s
 
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No, we're pretty much all on the same page. We're just differing on if youre running a rad in the top of your case and then intake vs exhaust. If youre not running a rad in the top then the top fans should be exhaust. Honestly I don't think it matters that much even if youre running a rad. I had better luck with my fans as intake as I picked up a couple degrees of extra cooling but there seem to be just as many people running them as exhaust and having good luck. Maybe I have luck with intake because my computer room is in the basement and usually cool like 69 degrees ambient and the cool air helps. If somebody else's computer room runs a little warmer, maybe the benefits aren't there. So Id say the best way if you have a rad in the top is to try different configurations and find the one that works best for your rig.
 
MacLeod said:
No, we're pretty much all on the same page. We're just differing on if youre running a rad in the top of your case and then intake vs exhaust. If youre not running a rad in the top then the top fans should be exhaust. Honestly I don't think it matters that much even if youre running a rad. I had better luck with my fans as intake as I picked up a couple degrees of extra cooling but there seem to be just as many people running them as exhaust and having good luck. Maybe I have luck with intake because my computer room is in the basement and usually cool like 69 degrees ambient and the cool air helps. If somebody else's computer room runs a little warmer, maybe the benefits aren't there. So Id say the best way if you have a rad in the top is to try different configurations and find the one that works best for your rig.
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Thats make A LOT of difference, 20C room temp its the main factor.. My test are based from 24C room temp to a high 35C all controlled... And this is cuz not all people have the conditions to keep the room temp at a constant low temp... Some others does not have air conditioner and live in hot places... Also I recommend that on radiators cuz many people that use water coolers make high overclocks on their systems keeping their chips on 70C-80C So the radiator exhaust high amount of warm/hot air and this have a high impact over the other components.. So thats why i meam the more successful case its keep the fans on the radiator as exhaust... For me as you keep my room temp on 21C my temps are really amazing.. OC'ing my i7 sandy 2600 to 4.3ghz. And able to reach a maximum of 50C on p95 27.9 as exhaust.. So as intake the temp its like 1-2C lower and does not make a big impact over the other components... As my case have the top side panel as intake. Even as intake the other components keep cool.. The thing its on this way all the airflow got really fcked.. And happens a really really over possitive air pressure inside the case.. So keeping it as exhaust, rear exhaust, front intake, bottom intake its more compensated the air flow.... And always go in same direction its more adequate enviroment... Not taking in consideration that i live on a high temp zone where the normal ambient temp its an average of 32C this make a BIG impact keeping the fans of the radiator as intake...
 
mhenley said:
This isn't a difficult concept, but people are making it out to be.
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For the most part that is right...for air cooling. but being that a rad sits right on a case opening, if he is having trouble with core temps and wants to reduce them, the best way is to turn the fans on the rad which is located on the back of the case to intake, and with the top fans being exhaust very little air should make it all the way back in the case as it will be pulled up and out. While he might see some higher temps inside the case if they are not having problems with it does not matter, most of the time RAM/Mobo etc are not temps people have problems with, the only problem he might have is if he has a pretty high OC on the GPU. The [H] also has a video/review somewhere of the H80 and they use the rear as intake, reason for it is because Corsair recommends it.
 
So out of curiosity I wanted to see just how much the rad was heating the air. I fired up OCCT and let it run for a few minutes and got temps bouncing around 50C. I got a cheap thermometer that's meant for your car's AC vent and sat it on top of the grill on top of the rad. Ambient temp going in was roughly 72F.

tempbefore_zps2d7f6cff.jpg


Here is my CPU meter and the Core Temp monitor showing 47 but it was bouncing up and down and holding mainly at 50C.

monitor_zpsfe3b8214.jpg


Then I held the thermometer directly under the fans and held it there for a couple minutes til it stopped climbing. Looks like it got up to 78F.

tempafter_zps60bd95a1.jpg


So I am a little surprised because I didn't think it was heating it up that much. But 6 degrees F isnt too big a deal I don't think and with all the intake fans I have running, I think its getting pushed out the back fairly quick because like I mentioned, Thermal Radar has never shown any unusual hot spots anywhere and at the end of the day, this was the configuration that resulted in the lowest CPU temps.
 
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BlueFireIce said:
For the most part that is right...for air cooling. but being that a rad sits right on a case opening, if he is having trouble with core temps and wants to reduce them, the best way is to turn the fans on the rad which is located on the back of the case to intake, and with the top fans being exhaust very little air should make it all the way back in the case as it will be pulled up and out. While he might see some higher temps inside the case if they are not having problems with it does not matter, most of the time RAM/Mobo etc are not temps people have problems with, the only problem he might have is if he has a pretty high OC on the GPU. The [H] also has a video/review somewhere of the H80 and they use the rear as intake, reason for it is because Corsair recommends it.
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Based on his original description I thought he was talking about the VRMs, but was calling them Vcores since that's what his temp sensors were reporting. You're right about Corsair recommending pulling fresh air from outside the case, since that will make their cooler run at it maximum potential, but at what cost since that heat gets dumped into the case. Some cases are better than others, but in his case the intake is severaly cripped due to 1: lack of fans, and 2: lack of clear path for the air to flow due to cable obstruction.
 
mhenley said:
Based on his original description I thought he was talking about the VRMs, but was calling them Vcores since that's what his temp sensors were reporting. You're right about Corsair recommending pulling fresh air from outside the case, since that will make their cooler run at it maximum potential, but at what cost since that heat gets dumped into the case. Some cases are better than others, but in his case the intake is severaly cripped due to 1: lack of fans, and 2: lack of clear path for the air to flow due to cable obstruction.
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That is true that the case and it's airflow matter. My little half assed experiment showed that with temps in the 50's, the air coming in thru the rad is 6 degrees more than the ambient. That's around 3C which isn't insignificant. But it does translate into better cooling for the CPU by a couple degrees C and doesn't appear to be causing problems with anything else. I guess it comes down to what works best for your rig and setup.
 
FearXI said:
This isn't a difficult concept, but people are making it out to be.

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This is a good setup.
My only change to it would be the rear fan being an intake to blow over the RAM.
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or if it is possible, dual side panel fan intake..this work great for me..
 
For radiators, you want the coolest air possible blowing on them. That means for a top radiator, you probably want the fans pushing or pulling into the case. That way the air blown across the radiator is as cold as possible and the most heat exchange happens. Of course, now you have warm air in your case that needs to be exhausted someplace. You can flip the fans and use them as exhaust fans if you want, but you'll lose out on performance on the CPU cooling.

The whole "top fan as exhaust because heat rises" thing is meaningless because in our computers we use fans. The fans blow air wherever they want it to go. What hot air does in a fanless environment is meaningless for actively cooled computers.
 
dealmaster said:
For radiators, you want the coolest air possible blowing on them. That means for a top radiator, you probably want the fans pushing or pulling into the case. That way the air blown across the radiator is as cold as possible and the most heat exchange happens. Of course, now you have warm air in your case that needs to be exhausted someplace. You can flip the fans and use them as exhaust fans if you want, but you'll lose out on performance on the CPU cooling.

The whole "top fan as exhaust because heat rises" thing is meaningless because in our computers we use fans. The fans blow air wherever they want it to go. What hot air does in a fanless environment is meaningless for actively cooled computers.
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That can cause more problems by heating up the other components such as RAM.
Worse thing you can do is having the heat from all rads pushing into the case.

You're forgetting a lot of other components that rely on cool air being blown in, you'll just shorten a lot of lifespan on things this way.
 
Never mind the air temp, it's the temp of the components that matters. If you run AIDA64 you'll see the hottest components on the Sabertooth are "Temp1" and "Temp2" -- the VRMs. There should be enough airflow through the case to keep those below 70C.
 
i persoanlly like it to suck in air if my cpu cooler is exhausting.
i turn my psu around so any air that is not sucked by the gpu, and also exhausted into my case, is sucked out along with the psu air
my side panel is used to exhaust also
i have one fan in front pushing air in.

doesnt get any warmer than 45 on full load.
i dunno about abmient air but i assume its less.

there are principles in flow. output dictates input in this case.
 
Personally I think you don&#8217;t need the top fan because it disrupts the front-to-back air flow. If you remove it and block-off the fan opening, you may notice improved temperatures (and less noise). That has been my experience with Lian-Li A17. A good air-cooled CPU heatsink will provide better incidental air flow to the nearby components.
 
bstrang6 said:
IDK how much cable management he's going to get more than he has with a non modular power supply.
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He could coil up the cables with cable ties and stuff them in the empty hard drive bays. Would be an improvement.
 
Simmonz said:
He could coil up the cables with cable ties and stuff them in the empty hard drive bays. Would be an improvement.
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Could even get a custom PSU shroud and cover most of the crap on the bottom nicely as well.
 
dealmaster said:
For radiators, you want the coolest air possible blowing on them. That means for a top radiator, you probably want the fans pushing or pulling into the case. That way the air blown across the radiator is as cold as possible and the most heat exchange happens. Of course, now you have warm air in your case that needs to be exhausted someplace. You can flip the fans and use them as exhaust fans if you want, but you'll lose out on performance on the CPU cooling.

The whole "top fan as exhaust because heat rises" thing is meaningless because in our computers we use fans. The fans blow air wherever they want it to go. What hot air does in a fanless environment is meaningless for actively cooled computers.
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Thats the way I see it as well. The air coming in thru the rad isnt that much warmer than the air going into it and with intake fans on the front and exhaust fans on the rear not to mention a side and bottom intake fan, those few degrees wont amount to much. My own half assed experiment only showed a couple degrees C increase. I suppose if you had no real case fans then it could cause some warmer than usual temps but if youre going to spring for a $120 CCL cooler, youre probably not going to have only 1 crappy case fan. :D
 
MacLeod said:
Thats the way I see it as well. The air coming in thru the rad isnt that much warmer than the air going into it and with intake fans on the front and exhaust fans on the rear not to mention a side and bottom intake fan, those few degrees wont amount to much. My own half assed experiment only showed a couple degrees C increase. I suppose if you had no real case fans then it could cause some warmer than usual temps but if youre going to spring for a $120 CCL cooler, youre probably not going to have only 1 crappy case fan. :D
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Your temps would be much lower if you have air blowing out of the case through the rads.
Usually the bigger rad being the one having the air pushed out.

Cooler air being pushed in by small rad (or front fans) and optional back fan will lower temps not just water temps but RAM and other important components and even the PSU.

By pushing it in you will raise the temps and even the temps of things you're trying to cool GPU and CPU.
 
FearXI said:
Your temps would be much lower if you have air blowing out of the case through the rads.
Usually the bigger rad being the one having the air pushed out.

Cooler air being pushed in by small rad (or front fans) and optional back fan will lower temps not just water temps but RAM and other important components and even the PSU.

By pushing it in you will raise the temps and even the temps of things you're trying to cool GPU and CPU.
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Unfortunately thats not the results I found. When I first got my H100 I tried it in 4 different configurations. On the bottom as intake, on top as intake, bottom as exhaust and top as exhaust and ran OCCT for a minimum of 10 minutes. Fans on the bottom, pulling cooler air in gave me the coolest CPU temps by 2-3C. GPU and motherboard temps didnt change in ANY of the configurations. I didnt expect they would since I have plenty of cool fresh air being blown into the case. I used Thermal Radar to monitor the motherboard, Core Temp to monitor CPU and the GPU Meter gadget to monitor GPU temps.

I give you my word. I would not have chosen this configuration if it didnt work best. If you have good intake fans, youll have much more cool air coming into the case than warm air and the warm air will get moved out the back of the case very quick. The air coming in thru the rad is only 2-3C warmer than ambient and its being met by a lot more ambient air so its not lingering around long enough to heat up anything.
 
MacLeod said:
Unfortunately thats not the results I found. When I first got my H100 I tried it in 4 different configurations. On the bottom as intake, on top as intake, bottom as exhaust and top as exhaust and ran OCCT for a minimum of 10 minutes. Fans on the bottom, pulling cooler air in gave me the coolest CPU temps by 2-3C. GPU and motherboard temps didnt change in ANY of the configurations. I didnt expect they would since I have plenty of cool fresh air being blown into the case. I used Thermal Radar to monitor the motherboard, Core Temp to monitor CPU and the GPU Meter gadget to monitor GPU temps.

I give you my word. I would not have chosen this configuration if it didnt work best. If you have good intake fans, youll have much more cool air coming into the case than warm air and the warm air will get moved out the back of the case very quick. The air coming in thru the rad is only 2-3C warmer than ambient and its being met by a lot more ambient air so its not lingering around long enough to heat up anything.
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Ah well that's a little different.
I'm talking about real water cooling as in GPU's and CPU will cause a lot more heat and that will harm the rest of the rig with how much heat you'll pump into the tower.

If I (or anyone else with a two rad system) pulled air in all my rads it would raise temps of everything. With one rad pulling in (lower small rad) and large pushing out keeps the temps in this custom water cooling keeps it cooler.

Now *maybe* if you pulled air in all rads and had plenty pulling out quickly it may work.
 
Heat rises in stagnant air, however, heated air molecules will flow in any direction air is moving. It is common practice to push air up because of that belief, however when you create a "tunnel" of air, you can push heat in any direction you wish. There is a trade off. The components in your system are creating heat, so as you pull air from the front of your system, and across the motherboard, you pickup heat, and then move it across your radiator. now we know from air cooling, you can only cool a component as cool as the air around it, so slightly warmer air has a lower cooling capacity than cooler air outside your case. If you pull fresh air from outside the case, and pass it directly across your radiator, the airs cooling capacity may be greater, however you will then be blowing more heated air into the case, so cooling capacity for other components in your right will be lower. As long as their are vent fans, the fact that they are lower than the intake fans will be of minimal consequence as long as flow is good.
That being said, I believe the position of the fans on your radiator is more important than where the air is coming from. If your fans are on top of your radiator, sucking air threw the radiator and then out of the case, Airflow will be laminar acrossed the radiator fins and cooling capacity will be reduced, Ideally you want your fans to blow "Into" the fins. The air passing close to the fins create turbulent air reducing laminar flow. While it may feel like at the top of the radiator, overall flow is reduced, The turbulent air ensures more air molecules are slamming into the cooling fins of the radiator removing more heat from them.
 
MacLeod said:
Unfortunately thats not the results I found. When I first got my H100 I tried it in 4 different configurations. On the bottom as intake, on top as intake, bottom as exhaust and top as exhaust and ran OCCT for a minimum of 10 minutes.
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What i think its you really need to make more exhaustive test.. a 10min test its not enough to test any configuration specially on that room temp, where take a LOT of time to the components to get hot... you wanna test pretty nice? make some couple hours of gaming, at least 3 hours of p95 Blend (27.9version). or Aida 64 on full System Stability Test that stress CPU, FPU, Cache, Hard drives, RAM and GPU.. and not in insane amounts... more or less what a heavy game (like Crysis 3, BF3) do..
 
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