Radiator Air Flow <--or-->

The Mobo and parts inside really don't worry about a few C higher. The water in the radiator, if it gets 3C higher air tempsit WILL increase your temps 3C higher. If your temps are fine with using case air to cool the rad air, then it's not an issue.

Here is actual tests, you can see the difference of air in/out on a radiator.

http://martin.skinneelabs.com/Swifte...20-Review.html

Scroll down to thermal testing, find the column for air in and air out. You can see it matters on the fan speed too, the longer the air is in the rad fins, the warmer the air is. It's also due to low speed rads not cooling the water as well, so the water is warmer too.

Lots of folks have a cool air into the rad in the front of the case and exhaust through another rad at the top of the case.

Of course, coolest air to the rad is best, but it's not a hard and fast rule. Depends on your needs and your stuff.

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getting the ambient air through the rad first will provide better temps as you cannot go below ambient with a normal wc setup.

as Conumdrum said, the mobo doesn't mind the little bit of extra heat.

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thorilan said:

they pretty much covered it but there is one other reason you may want to consider before deciding.
if there isnt a lot of room in the case so the fans have to be right up against the rad , you will get a different sound in push than you will in pull.
it may or may not be detectable and usually is only noticeable on high fin per inch rads but it can be there.

many people dont realize just how important it is to get the right kind of fan for the rad .
some companies are famous for this because they want to lower the cost of thier units so they may have a good product but stick a not well matched cheepo fan on it to keep cost down.
what they dont realize is we would rather have no fan at all and save more money when getting high end products and choose our own custom fans.

as to why the sound is different in push and pull, it has to do with how the air hits the rad and how much of it rebounds off the edge of the fin. it can make noises that range from a whistling sound to a vibrating hum to a low moaning sound in push and sometimes in pull you can get a toilet flushing whosh sound.
there are so many combos that its hard to say but i have noticed over there years that generally i get anywhere from 3-8 db less noise in pull based rigs IF it is properly sealed meaning no air leaks from other parts of the case.

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thorilan said:

they pretty much covered it but there is one other reason you may want to consider before deciding.
if there isnt a lot of room in the case so the fans have to be right up against the rad , you will get a different sound in push than you will in pull.
it may or may not be detectable and usually is only noticeable on high fin per inch rads but it can be there.

many people dont realize just how important it is to get the right kind of fan for the rad .
some companies are famous for this because they want to lower the cost of thier units so they may have a good product but stick a not well matched cheepo fan on it to keep cost down.
what they dont realize is we would rather have no fan at all and save more money when getting high end products and choose our own custom fans.

as to why the sound is different in push and pull, it has to do with how the air hits the rad and how much of it rebounds off the edge of the fin. it can make noises that range from a whistling sound to a vibrating hum to a low moaning sound in push and sometimes in pull you can get a toilet flushing whosh sound.
there are so many combos that its hard to say but i have noticed over there years that generally i get anywhere from 3-8 db less noise in pull based rigs IF it is properly sealed meaning no air leaks from other parts of the case.

Click to expand...

Conumdrum said:

A shroud also gets the fan far enough away so the motor hub (which has no blades) isn't close to the rad surface. This gives you a bit more partial surface area. It also makes room for the air flow to become more lamilar, smoother. It's more efficient flowing through the fins and 'can' reduce some noise and increase the CFM of the fans.

Some modern rads have a built-in shroud, called a plenum (same thing) of 10mm or so. But only on one side of the rad. Something to look at as you buy a rad.

Lastly, if your rad is too small for your heatload, a shroud can give you performance increases (mentioned above). A bit cooler water. Say your DT is 15C, very high (bad). You get a 10% improvement or so, thats 1.5C! But if your DT is low because you got plenty of rad, say a DT of 5C, you'd only get a .5 decrease in water temps. Might not be worth the trouble or money to worry about a shroud.

Very few of us have a purpose built shroud on any of our rads here, for the above reason.

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Only thing I could possibly add to this is you could get variable speed controlled fans. These will let you set the speeds they run at and at the same time, have some control to how much noise they make as they run. I have three 120mm fans on a triple rad and if I'm doing some heavy OC'ing, I turn them up and if doing some moderate to light gaming or just not wanting to hear the noise, I just turn them down to where I want them.
Of course you'll need to monitor temps and see what fan speeds work best with your paticular setup with what you're doing at the time if you get some of these.
If you don't have it already, this can be done with HWmonitor.
http://www.cpuid.com/hwmonitor.php

On a side note, my triple rad is mounted completely out and away from my case, so it does not have any case air passing through. The case itself has 5 fans; Three 80mm's and a pair of 120mm's in it. The case is one I picked up awhile back, a Sunbeam Transformer full tower case. It may be big, but it actually fits on my desktop and does the job.

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noxqzs: One popular method for making a shroud is taking old fans and stripping everything but the shell and using them as spacers.

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