Air circulation for CPU.

[cajun_duck]

I am not understanding this too much. You see combos with a fan facing front to back and some facing the cpu. What is the best way to go? I have a Prescott P4, 3GHz, 800fb. What would you suggest to cool it? Plus, which way should the fan face?

[a.Bird]

I'm not sure if I understand what you mean by "combo" but if you have traditional rectangular heatsink on your cpu with a top mount fan that is parallel to the cpu, the fan should blow towards it as opposed to away from it. The heatsink aborbs the heat from the cpu and the air blowing onto it whisks the heat away.

When you say "front to back", do you mean case fans or a heat sink with a fan mounted perpendicular to the cpu? Generally for most cases that are built like any other, it's best to suck air from the front of the case and direct it towards back since your psu probably exhales hot air out of the rear of your case. If you are a referring to a cpu fan mounted perpendicular on a heatsink, it depends mostly on your case design but in general I would suggest having the fan blow towards the back if you have rear exhaust fans or else you will create too much air turbulence. If you have an exhaust fan on the top of your case, point the cpu fan UP.

That may have sounded like a mouthful but if I can leave you with anything let it be this: If you are air cooling, get rid of the heat in your case with the most direct, unobstructed gust of wind possible. Sucking air into your case from all sides with five 80mm fans is usually less efficient than one large (120mm) intake fan in the front and one large (120mm) exhaust fan in the back. Why? Air turbulence- the air just whirls around in your case instead of getting heat out of it. If the fan on your cpu blows directly towards the cpu, align heatsink so that the slots are parallel the general flow of air in your case. If the fan is perpendicular to the cpu, direct it towards the exhaust.

I probably should have just let one of you pros say the same thing in fewer words. :P

[cajun_duck]

Thats what I'm talking about, parralell and perpendicular. What is the best to go. I will have a 120 at the front bottom, a 120 at the top rear, a 120 on the side, and mesh grills at the top.

[Redundant]

If you get a heatsink that faces down towards the CPU, make sure your side fan (if it's over the CPU area) is blowing inwards.

If your heatsink follows the stream of air (front of case to back), it's usually more efficient. Here's an example (http://www.newegg.com/Product/Product.aspx?Item=N82E16835118223) of this kind of HSF. And a pic of it installed. (http://www.thebestcasescenario.com/forum/showpost.php?p=84346&postcount=5)

Where on the side of the case is the fan?

[cajun_duck]

but which is better?

[Silenced_Coyote]

I'm not sure which is better because it is hard to compare something like this. But I prefer the heatsink/fan sitting perpindicular to the motherboard. I like the idea of it blowing air directly towards an exhaust fan.

[a.Bird]

Some heat sinks are copper, some aluminum, others both. Some fans push air more efficiently than others. Some units have heat pipes. Some units are less than $15, others are more than $50. Some have perpendicular fans and others parallel. It really depends on all the factors combined because if the fan is mounted differently, well then that means the heat sink is built differently and then you are in a completely new ballpark. Sooo, go to http://www.newegg.com , search for cpu coolers specific to your defined needs (price, noise level, socket type, etc.) and sort the list by rating. Then slowly research the units from top down and read what experienced users have to say about the product. Many times, the people reviewing the items will note whether or not it made a big difference from their stock fans (almost any after-market cooler does) as well as what their processor is and what their actual temperatures were. If you post your socket type, how much you're willing to spend, how much room you have in your case for a cooler, how quiet you need it to be, etc., then I'm sure almost anyone here can recommend a quality unit for you.

[azminisk8r]

for a p4 if you really want coolign id suggest this quiet and cool
http://www.newegg.com/Product/Product.aspx?Item=N82E16835186134

[a.Bird]

Yup and here is another good one rated at 16 dBA which is hardly noticeable. Thermaltake CL-P0114 120mm CPU Cooler (http://www.newegg.com/product/product.asp?item=N82E16835106061) $44.99

[azminisk8r]

yeah those two have got to be the quietest between being paralell and perpendicular, btw first one is 17 dba still not noticeable, 21 barely is