Top mounted rads, noise, positive case pressure

[omaticrail]

I'm well read concerning front-mounted dual cores, and their advantages. What bothers me about them is the expense of well-suited cases, the fact that you still end up cutting them all up, and that you either gain a lot of height (case choice) or lose too many front slots.

Front-mounting a dual core just seems like a much bigger pain than it's worth, but that depends on one's definition of "pain" and "worth."

I've pretty much concluded that top-mounting is both easier and cheaper. So much so that I believe one could top mount a tripple-core easier and cheaper than a front-mount dual, mostly due to the suitability of cases, and their associated prices.

So, I'd love to hear from those that have experimented with top mounting. Right from the start I can guess at some of the issues/compromises. For discussion's sake, let's assume that I will water cool the CPU and GPU.
Upward airflow issues:

Exhausting case air through the rad. Not good, but maybe not as bad as I'm imagining if everything is water cooled.
Negative case pressure = more dust, plus chance of pulling in warm air from behind the case.
Fan's on the very top (pull up config) are closest to user's ears.

Downward airflow issues:

Air temp above a case is virtually guaranteed to be at least slightly warmer than air from the front, especially under a desk where furnace vents and the PC itself dump lots of heat.
Fans, while marginally more insulated from the user's ears than the upward flow, are still going to be more louder than a front-mount.


Has anyone tried TOTALLY refersing conventional airflow, using inward facing fans at the top or back? How would the PSU factor into that mess? What about bottom mounted PSUs, such as are used in the Antec P180?

Let the ruckus begin!

[Slammin]

On my Antec P-160, I originally started out with the Swiftech-120 kit. The rad with that kit fit perfectly internal in the 120mm rear fan exhaust hole. After adding my GPU to the loop, that rad was not enough so I cut a 120mm hole in the top and added a 120 h/c. I put the fan on the original 120 rad in a pull/intake config and I put the top fan in a pull/exhaust config and this worked out very well for me.

Alternatively, I could have really gone crazy with the dremel and cut out enough bays in the bottom front to do a dual 120 since putting the single 120 h/c in the top did require me to lose 1 5/14 bay, but putting a dual down low would have meant losing all of my 3 1/2 bays and probably one 5 1/4 too.

The 120rad with 120 h/c really worked out well and I kept the 25mm fans at 7v with an adapter I made, so it is extremely quiet too.

[Rpkole]

well i never have tryed a top mounted rad but i think it sounds like a good idea. Guess i will try it on my next system :p right now i got a dual 120 in the front of a CM Stacker which works great cause there is no cutting and still have two 5 1/4 bays and four 3 1/2 that i can use

[omaticrail]

...right now i got a dual 120 in the front of a CM Stacker which works great cause there is no cutting...
Rpkole, is that a dual 120 HC or a narrower rad like the BIP2? The Stacker is currently my favored case, assuming I go with a front-mount. I've never seen one, and even the few case projects I've seen did discuss various degrees of cutting involved.

[Hey_Its_Cole]

I did not have to cut at all with my stacker, with the weapon shroud, it wedges securely without need of anything to hold it in place.

[Tat2monsta]

well i never have tryed a top mounted rad but i think it sounds like a good idea. Guess i will try it on my next system :p right now i got a dual 120 in the front of a CM Stacker which works great cause there is no cutting and still have two 5 1/4 bays and four 3 1/2 that i can use


oooh i got the tt armor. which is just like a stacker. and i wanna add a double 120mm rad. will take up a few slots.. but hey who cares ive got 11 on this monster.. my question thoe is.. where ya got your fans? behind sukin though the case?or in the front pushin or pulling out even? i was maybe thinking having them inside pullin then have another 120 at the back.. cpu and gpu will have blocks. so there shouldnt be to much extra heat. any ideas? piks b4 the change.. havent ordered anything yet http://photobucket.com/albums/b208/tat2monsta/my%20pc/

[SewerBeing]

as far as top mounted rads go: I don't think it matters either way. If you put a finger grill and a filter then having it blow air into the case would be easier (filter before the radiator or else that gets clogged with dust). Then you could use the rear (and side) fans as exhaust. If you can balance that airflow you would probably be in good shape. What you could also do as an extension is add a fan in the front to suck in air and then have the rear (and side) fans as exhausts (just balance that). Whatever you do, remember your filters.

If you want the top as exhaust then I suggest having the rear and front fans as intake (balance is key and filters on the intake).

If you can balance the fan power then you should be in excellent shape as long as the intakes are filtered. Also put filters over any holes or gaps in the case where air may go in. Finally remember to clean your filters regularly.

One last thing to consider, most radiators perform better when you pull air through vs pushing it through the rad.

[y2jed_2000]

this is how mine is setup on my gaming rig, sorry about the low quality, stupid camera phones

[alinosa]

well with my setup (this was right before i put it all in a plexi box... which is ugly, i need to put it all back ionside my case). i had the radiator (BIX3) mounted outside the case on the top with the fans inside. the case top-plate was sandwiched between the fans and the rad. the fans pulled air into the case. all 3 sanyo denki's are on a nexus fan controller that can handle something like 18W per channel (3 channels). all my fans were set at just a high enough voltage to get them spinning and no more. any faster and i got practically zero additional cooling since i'm only cooling my cpu right now. this was very quiet. it also eliminated the need for case fans ( but i still have a couple), and fans for the hdd's (3 80 GB ea.). the pressure was enough to force air between the hdd's and out the front of the case (it's a chenming dragon or whatever it's called) and the two 80 mm in the back keep the pressure from getting too high

[[O-CuK]Marci]

Top mounted triple rad in Chieftec Dragon, with side fans providing balanced extraction.

Air in at the top, in at the front, out at the back, out on the sides...

http://marci.over-clock.com/2003ptII/images/DSC00106.jpg

http://marci.over-clock.com/2003ptII/images/DSC00115.jpg

http://marci.over-clock.com/2003ptII/images/DSC00118.jpg

Done loadsa cases the same... never had any major impact on internal case temps other than with pelt rigs... in which case flip fans to take air from in to out instead of vice versa.

[grunjee]

Not adding much to this thread, but Marci that is a beautiful setup.

I've always top-mounted my (single fan heater core) rad in my Lian-Li cases... it's always worked fine for me. Although the noise factor is the only downside... as you said, it's close to your ears so you notice it.

And I have never experiemented with reversing airflow - to face my fan inward... just doesn't seem logical to me.

[Tat2monsta]

ive just gone for a rad in the front of my modded armor case.. only just built this thing with many thanks to over-clock very quik delivery and very helpfull over the phone.. pik below shows air direction. i chose this as i didnt want air being sucked in the front and ending up with an inch of dust on my nice new rad within a week. as it goes its keeping temps low.. loaded with bf2 and prime. 36c noise aint to bad. no louder than my gf's air cooled pc in the same room.. have quite a lot of space behind the desk for the air intake. and it isnt even collecting any dust yet! also having the fan blowing in at the back keeps my ram pretty cool. well one side of it atleast and my nb is way cooler