Top Radiator .. Intake or Exhaust?

[Postmodum]

So i'm building my new case and i have some doubts on what to do on the top radiator ...

Basically i'm using a 420 and a 280 BlackIce GTX radiator with push-pull 140mm fan configuration...

But i'm having some problems on how to do the air flow...

So i have these 2 options ( blue rectangles are intake fans, red are exhaust ) :



My inicial thoughts were to just leave the rear fan as an exhaust and use both rads as intakes ... this way they would get fresher air improving the performance.

The front fan is a 180mm Silverstone Air Penetrator that will have a clear path for the air flow, so it will be able to intake the cold air to the end of the case... "pushing" the hot air for the rear exhaust fan and case openings...

What do you think it's the best option? The left drawing or the right drawing?

Here's actual photos of the case...









Components to be cooled
- CPU
- Chipset
- The VGA will be cooled as soon as the water block for it is launched...


Thank you for your help.
( I already asked Martin for some help but i don't want to take him much time with private messages, so i'm putting this as a topic here )

[zalbard]

The way I see it 1 will result in somewhat cooler air going through the top rad but will increase the air temp inside of your case. 2 will have slightly warmer air going through the second rad, but the air temp inside the case should be a lot better. I'd go with #2.

[Scubar]

im doing a somewhat similar thing to yours in my new build. I have a top rad and a front rad.

The front rad im using as an intake and then having a quad in the roof as an exhaust along with the 120mm fan on the back also.

Id say go with #2

[Sideroxylon]

Using a rad as an exhaust is a loss in performance and a waste IMO. Option #1 for best performance.

[Scubar]

Using a rad as an exhaust is a loss in performance and a waste IMO. Option #1 for best performance.

If he goes with #1 then there will be too much internal air pressure of which it will be warm air. This would then warm all of the components up that he is trying to cool taking away all of the benefits.

[Coolgate]

I would go with the right drawing, this is the better choice for air flow, maybe you must consider also the air flow of power unit.

[musicfan]

I have a HAF 932 with a 120.3 up top and had to decide. My logic was the same as zalbard. I chose the option on the right.

I think it depends on whether you have enough rad to cool your blocks. If you have low load temps, then the option on the right may cool your case/RAM/mobo better. But if your load temps in your water-block components are too high, then using cooler ambient will improve block performance. Good luck.

[Manicdan]

i would do something a little different

go with picture 1, but swap the front fan to be exhaust in addition to the back one. hopefully you can rotate that fan. then you still have the coldest air for both rads, and your more balanced for intakes and exhausts.

[PiLsY]

Both rads and the rear fan as exhaust should give you best temps overall. Any air you blow into your case through a rad will raise case temp. Setting every rad as exhaust should in most cases give you best overall loop temps.

[jcrouse]

Both rads and the rear fan as exhaust should give you best temps overall. Any air you blow into your case through a rad will raise case temp. Setting every rad as exhaust should in most cases give you best overall loop temps.

I would have to disagree here, since you are pulling warm air through the rad as opposed to intake through the rads, which in most cases (if ambient is lower than internal temp) would be pulling cooler air through the rad.

John

[Sideroxylon]

If he goes with #1 then there will be too much internal air pressure of which it will be warm air. This would then warm all of the components up that he is trying to cool taking away all of the benefits.

You make it sound like our cases are air tight. That's not the case.There's more than enough places his fans will exhaust to. Anything he's air cooling in his case won't be affected by the slightly warmer air from his rads. It's not like they'll be blowing 80c air into the case. At most, with that setup, his rads will be blowing 5-10c aver ambient into his case. Anything he's water cooling won't be affected at all.

Both rads and the rear fan as exhaust should give you best temps overall. Any air you blow into your case through a rad will raise case temp. Setting every rad as exhaust should in most cases give you best overall loop temps.

What?!?! Why would blowing heated case air through a rad give you best temps? This is a ridiculous statement and goes against the basic principles on how rads work.

[NaeKuh]

LOLOLOL... i want to read the comments people write and see there thinking....

Both rads and the rear fan as exhaust should give you best temps overall. Any air you blow into your case through a rad will raise case temp. Setting every rad as exhaust should in most cases give you best overall loop temps.

so you really think him pulling air though the rads and out at the top will lower temps?

Do you not see those mosfets hanging right below the top rad?
Do you know how hot those guys can get and how much they can change ambients?

Wouldnt you rather have air being blown on them from the top, then have to pull air from them?

I would have to disagree here, since you are pulling warm air through the rad as opposed to intake through the rads, which in most cases (if ambient is lower than internal temp) would be pulling cooler air through the rad.
John

Well from the looks of things... it doesnt look like he's a pack rat.
I dont see no spider webs with fan headers, or even him trying to spell his name in cursive using the power cables..

Do you honestly think there is going to be more then 1-2C delta different @ intake on his rad?

You make it sound like our cases are air tight. That's not the case.There's more than enough places his fans will exhaust to. Anything he's air cooling in his case won't be affected by the slightly warmer air from his rads. It's not like they'll be blowing 80c air into the case. At most, with that setup, his rads will be blowing 5-10c aver ambient into his case. Anything he's water cooling won't be affected at all.
.

Bingo! Ding ding ding!

This guy deserves a cookie.


Its true, at most the rad will absorb 60-75% of air.
Then spits the rest out.... what does that mean?

If the air going in and out of the rad is more then 2C, then by gosh, you have one hell of an efficient radiator.

[jcrouse]

LOLOLOL... i want to read the comments people write and see there thinking....

If the air going in and out of the rad is more then 2C, then by gosh, you have one hell of an efficient radiator.

Well ... I am new, but according to my readings, most of the water is stabalized at at approximately the same temperature throughout the loop, so this is a somewhat bogus statement.

Following your logic, I must ask, why even use a rad if the water exiting is within 2 degrees of what enters? I am guessing, but logic tells me, the more rad (all other things even) the lower the temps, hence the rad cools things down, even though the entry and exit temps are similar.

John

[NaeKuh]

Well ... I am new, but according to my readings, most of the water is stabalized at at approximately the same temperature throughout the loop, so this is a somewhat bogus statement.

Following your logic, I must ask, why even use a rad if the water exiting is within 2 degrees of what enters? I am guessing, but logic tells me, the more rad (all other things even) the lower the temps, hence the rad cools things down, even though the entry and exit temps are similar.

John

yeah but look at saturation.

as i said a MCR320 does about 60% at best your going to get 75% saturation.

So that means 25% of the air is unused and gets passed along.

So out of the 75% saturation, do you really think the delta of air going in and out is going to be that big?

[PiLsY]

What?!?! Why would blowing heated case air through a rad give you best temps? This is a ridiculous statement and goes against the basic principles on how rads work.

If your case has good airflow your "heated" case air will be at most 1c over ambient. Please remember you're watercooling and the majority of stuff that makes heat in your case is now in the loop and applies its heat through the rads. Lots of mechanical hard disks can heat your case up but if you're imaginative and place them near an exhaust and not an intake that is not a problem. There is no reason why case air blown into a rad should be warm, let alone hot.

[Scubar]

If your blowing warm air into the case you will be heating up not only all the other components but also the waterblocks themselves which will then be transferring the heat from the blocks aswell as the warm air inside the case which. Ive felt the warm air my Rads pump out when everything is under full load i wouldnt want that pumped back into my case.

[Sideroxylon]

If your blowing warm air into the case you will be heating up not only all the other components but also the waterblocks themselves which will then be transferring the heat from the blocks aswell as the warm air inside the case which. Ive felt the warm air my Rads pump out when everything is under full load i wouldnt want that pumped back into my case.

You're seriously confused if you think the air blowing over a waterblock will overcome the effects from the watercooling itself. It's why we watercool in the first place. We take air's effect on the thing we're cooling out of the equation. Only thing air has to do with it is how cool of air we're feeding to our rads. That's what effects our temps to the things we watercool, not the air blowing on the block.

[coolmiester]

Hey i read all the comments from the water wizards who cant seem to decide which set-up would be best, why not the OP try it both ways as it wouldn’t take much testing given the current situation and let us all know the outcome???

I'd rather test it myself than rely on hearsay and that way you're sure to get it right

[theseeker]

Option 2 would be my choice.

[lilmanmgf]

Honestly I think you will be fine with either. Really with the loop you have the only thing putting off heat inside the case will be the ram and harddrives. The top just seems to be a natural exhaust. I have two 360 rads internal in the same case currently, with intakes in the front and bottom and exhausts at the rear and top. My cpu stays in the 50s during games, and my gpu stays under 40.

[lilmanmgf]

I'm sorry, I'm used to it being in my sig. i7 930@ 4ghz. Ambient temp: 22c. My GPU and CPU are both watercooled. The difference between using the top as an exhaust and intake was insignificant.

[Sparky]

I'm running a radiator in the top, and a front and a rear fan. Front and rear fans are intake, radiator is exhaust.

My temps suck lol. I can drop CPU temps alone by several degrees just by opening the side panel of my case I need to redesign but I'm still not liking the idea of intaking from the top since that goes against my brain waves of "heat rises"

[BrokenArrow]

I'm still not liking the idea of intaking from the top since that goes against my brain waves of "heat rises"

Convection of "heat rising" is so easily overcome by the weakest radiator fans sucking in cold air.

For God's sake people, it only takes a few minutes to change a fan's direction, please experiment both ways and determine what works best for your rig.

As coolmeister said, too many variables and to each his own.

This is suppose to be a hobby and experimenting should be part of the fun instead of posting for advice.

[PatRaceTin]

interesting

[PiLsY]

I've got floor, rear and top rads as exhaust at the moment. I tried the bottom as intake and the top and rear as exhaust - loop component temps went up by about 1c and case temp went up by almost 2c. Using all rads as exhaust everywhere i measure air temp inside the case is within 0.5c of ambient temp.

My case temp definitely goes up if any of my rads are set as intake. I have only tested with the fans at around 800rpm though. I'd imagine with higher fan speeds the trend would equalise and then reverse.

I can see what you're saying naekuh about those mosfets though. In my case I don't suffer for mosfet temps (under 50c even in linx) and I've got good clearance between the rads and the board - they're near nothing hot tbh.

rge makes a good point too - if mobo cooling as a concern in any way then blowing air across it will give better temps.

Think BrokenArrow said it best though. You should be taking the posts here as opinions - its up to you to figure out which will work best. I think you can see from the posts here though that whatever you try will work, but you'll have to experiment to find the best setup for your particular rig. In the grand scheme of things swapping fans round on rads really is about as easy as you can get for a loop rebuild . A large part of the fun in this hobby is getting the most from your loop and the countless amounts of configuration changes you can experiment with.