Why is the radiator positioned on top of the case?

[shmulikiv]

Hi
I'm quite new to liquid cooling and there is something that I can't understand it's logic.
As far I know case cooling mechanism works by cool air flows from the case front through the interior and over the mobo absorbs the heat and warms up and than flows out from top and rear of the case. If this air is warm why let it flow through the radiator that is installed over the top opening of the case?
Doesn't it degrades the radiator effectiveness?
Have I missed something?
I'll be most grateful for any eye opening responds
Thanks in advance
Shmulik

 

[MacLeod]

A lot of people that have the rad on top of the case like I do with my 500R and H100, they have the fans running as intake. This brings in cooler air from the outside and flows over the rad fins. Axial fans suck better than blow so I have the fans on the bottom of the rad pulling the cooler air in. I tried it every possible way and this was the configuration that gave me the best results.

Hot air does rise but thats in a static environment, which the inside of your case is anything but. Take my case for instance, Ive got 2 120mm intake fans on the front, a 200mm intake fan on the side, a 120mm intake fan on the bottom and a 120mm exhaust fan on the rear. With this much air flow, the air inside the case isnt getting as warm as youd think and its not going to rise but rather go with the flow of the air which is out the back.

So yeah, having the radiator on the top of the case can work just fine and if youre doing top intake fans, all the better.

 

[S_I_N]

also due to the fact its normally unrestricted space outside of the mobos heat sinks. The floor normally has the psu which can take up considerable room the front has the bays most of which take modding to remove and place a rad there.

 

[MacLeod]

also due to the fact its normally unrestricted space outside of the mobos heat sinks. The floor normally has the psu which can take up considerable room the front has the bays most of which take modding to remove and place a rad there.

Good point. Ive seen some modded cases with the rad in the front and I think that would be the ideal place since its lower and would theoretically be the coolest air coming in. The differences though arent that much. When I tried different configurations with mine, the top mounted with fans running intake was the best but only by around 2C so its not a HUGE difference really unless youre going for the maximum overclock and trying to wring every MHz you can out of your chip.

 

[shmulikiv]

Ok. Thanks a lot. That makes sence
I have a Zalman MS1000-HS2 with front(behind HDs) 2x90mm, bottom 120mm, rear 120mm and top 2x120mm which I intend to replace with H100i or H110.
I'm currently cooling my CPU with Thermalright Ultra 120 eXtreme which is OK but I want more for my OC.
Thanks for clarifying my misunderstanding.
Shmulik

 

[SuB]

Most of the time if you're watercooling with something that requires top-of-case radspace, you're usually removing or reducing the heat source that is dumping heat into that airflow, and putting this into the water temperature isntead, thus, if you cooled this *first* the air would then come into the case pre-heated and wouldn't have as much cooling capacity for any items that need passive cooling on the motherboard etc.

You could argue it either way to be honest, factors these days are more about asthetics, ease of installation (think, bleeding air from a radiator) and personal preference. It isn't going to change by much if you chuck a radiator in the top bottom or front these days.

 

[tinytomlogan]

A lot of people that have the rad on top of the case like I do with my 500R and H100, they have the fans running as intake. This brings in cooler air from the outside and flows over the rad fins. .

Apart from this is actually wrong

 

[Tripp]

i gotta agree with tom on this

 

[Feronix]

Same.

Most people run the rear fan as a filtered intake. This will feed the radiator cool air as well as passively cool the motherboard/ram better.

 

[Tripp]

Same.

Most people run the rear fan as a filtered intake. This will feed the radiator cool air as well as passively cool the motherboard/ram better.

yeah thats exactly how mine is set up

 

[MacLeod]

Apart from this is actually wrong

How is that wrong? I didn't say everybody did it that way, but a lot do. If I'm not mistaken, Corsair even recommends the H100 be run as intake when used in the 500R. I tried it as intake and exhaust and it worked better as intake. Doesn't seem wrong to me.

 

[Roooker]

I have my H100i rad in the top, because it just fits best there.
GPU dispensing hot air inside the case.

I also have ALL my fans running below 600 rpm.

2500k @4,2 1,35V (i know it is a lot) temps below 65.


Don't quite understand the point of asking why rads are in the top ?
Maybe because they fit there best ?