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Case cooling question

by abstraqts / August 21, 2005 8:43 AM PDT

I have a number of questions about cooling. I was provided with a number of computer-building guides by several helpful people in these forums earlier, but none of them talk about cooling.

1. I was told that a heatsink should be always put on the top of the case for the best ventillation possible. What exactly is a heatsink? How do you install one?

2. If there are no holes in the top of the case, they have to be drilled in so that air can actually get out?

3. Are fans only installed where there are air holes?

4. Do fans push more air if they have a higher RPM? Is higher better?

Thank you for your time.

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I doubt if anyone said to put the heat sink there.
by Ray Harinec / August 21, 2005 9:06 AM PDT
In reply to: Case cooling question

One has no choice where a heatsink(s) go/goes. It might of been this writer because I always recommend using a case with a top EXHAUST FAN, and a side INTAKE [if they come as exhaust, reverse it]. If they come with those fans they may not include the others, but always p[rovide places to mount others. I always add a front intake and rear exhaust.

If you want a link to such cases, tell me the size case that you want and I can give you links to them in newegg.

With adequate top and side fans, go easy on the rpm. The higher the rpm the more noise. Reasonable rpm fans properly located are fine.

There might be a special case where one might want to put a very small fan in front of a hard drive. Most hard drives are located low in the case and a front intake fan moves the air around them adequately.

The cases provide enough mounting places.

Only cut a hole in the top of one because the way it was assembled the top came off with one screw and the sides then came off. Got it only because of Black and Silver and roll down front for the CD bays. Thus it was easy to locate the fan such that it doesn't interfere with any structure. Not worth it unless one wants this specific case.

A heatsink is a metal, iron, copper, aluminum block of metal with numerous fins. The heatsink mounts directly to the component it is intended to cool. There is always a heatsink with a fan on the CPU it's called HSF. The purpose of the fins is to dramatically increase the surfae area over which the heat from the component can be dissipated over. Some chips have a heat sink but no fan. The heat leavwes by natural convection [heat rises], a fan provides forced convection and can move much more heat away from the device.

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The front intake would be the most likely
by Ray Harinec / August 21, 2005 9:12 AM PDT

to leave out if necessary. The air for most of them comes in through the very bottom of the case and goes up between the front plastic of the case and the metal structure of the case interior. Thus, if the tower sits on the floor, it is always pulling in dust, no matter how good a housekeeper you are. I always use the front intake but have the tower at least four inches above the floor and slightly back a lttle from the front edge of the mounting block.

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I was actually considering the...
by abstraqts / August 21, 2005 12:30 PM PDT

Cooler Master Praetorian 730:

It has two 80mm fans in the back, one 120mm fan in the front and one 120mm fan on the side. Plus some other heat dispersion thing on the side (I'm sorry, I'm just getting into building computers).

Please show me one of the cases that you were talking about. And can you please show me, on Newegg, exactly what an exhaust and intake fan looks like?

Thank you.

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Well you went to the correct place.
by Ray Harinec / August 21, 2005 11:11 PM PDT

And assume that you have looked at the photos enlarged. Thus you can do that for all of the cases.

It does NOT show a side 120 mm fan. You will notice on the door a cup like thing. That is to allow external ambient air to be provided almost directly to the CPU/HSF. That can easily be replaced by a 80mm fan if you would prefer. [you buy the fan separately. The link clearly says one 120 mm fan, one 80 mm fan and the side air duct. If you search down to the specs you see only one and one.

No need to apologize, be proud that you are willing to put the effort into learning so you get what you want the first time.

BEWARE, the photo does NOT match the descrription. Note the pictures from the rear, they clearly show two 80 mm fans places.

Now I have bought two or three smaller cases same model same mfr, one would come with a single punch out that would take a 120 mm fan [or any smaller one] while the other two had the the punch outs for two 80 mm fans.

Note that newegg warns that the photos may not be exactly the same.

The photo inside the case is not clear enough to see it because of the other stuff in the interior front, but it is highly likely there is a mounting punch out for a front fan. [not needed].

I'll post this and follow with another link or two and links to fan pictures [exhaust and intake fans are identical, simply whether one mounts them to pull air in or blow it out.

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You're right! It doesn't match!
by abstraqts / August 22, 2005 2:07 AM PDT

Good thing you pointed that out. I will want to buy from another dealer then... I read somewhere that you can mount a fan on the side. There is a clear picture of it here:


It no doubt looks like air holes.

Cooler Master's website also states that there is an "optional space on top" (under Key Features).


Is it possible to take out the I/O panel and use it for a space for a fan? If so (that is probably what they mean by the optional space on top), what will the hole look like? Instead of having airholes, will it be some big black gap on top of my case?

The reason I am pushing this case is because it seems very well-made and very functional, and its non-flashy but good looks are a big plus.

Thank you!

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Oooh! I got it!
by abstraqts / August 22, 2005 2:11 AM PDT

The Praetorian comes in two models - the 730 and the 732. The 732, it seems, has the two 80mm fans in the back, the 120mm fan in the front, the optional 120mm fan on the side and the optional 80mm fan on the top. Read the 732's specifications here:


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That site answered most of my cooling questions.
by abstraqts / August 22, 2005 2:19 AM PDT
In reply to: Oooh! I got it!

I will keep all of you posted. Thank you for your time.

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by abstraqts / August 22, 2005 2:28 AM PDT
In reply to: Oooh! I got it!

Nope, I was wrong... The 730 and 732 only has a difference in their front door. I don't know why Newegg has the model with only one 80mm fan in the back instead of two.

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The photo shows two places for the rear
by Ray Harinec / August 22, 2005 4:32 AM PDT
In reply to: Nope...

80 mm fans, the standard only comes with one fan installed. Other photos seem to show two mpounted wit fans with blue LEDS, or else the color lighting could be from inside somewhere else.

It can get confusing.

I have two cases similar to the thermal take, with the top exhaust and the side fans on a clear plastic hinged plate under the outside plate. They came with only one fan mounted to the side even though there were places for two. But with that case you get 5 fans with the basic price.

Aluminum cases are much lighter, but do not get fooled into thinking that they provide better cooling, the heat ransfer through the case for aluminum and steel is virtually the same. The way to get rid of the computer's heat is fans moving cooler air in and hotter air out. This far exceeds the heat transfer through the case.

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Only question that I have is
by Ray Harinec / August 22, 2005 3:57 AM PDT
In reply to: Oooh! I got it!

the top fan being an INTAKE, Since heat rises the hot air is at the top of the case, removing that will allow more heat to rise and get exhausted.

It is NOT like airconditioning a room. In a room you DO bring the cold air in the top of the wall. Since hot air rises the rising air forces the cool air down and the natural convection creartes a vertical circulation of air. In the computer case, the air you would be bringing in is really not very cool, the other fans will have forced circulation in the horizontal plane, simply overwhelming the natural vertical convection, thus you need the fan to exhaust [suck the hot air up] to have vertical convection.

Although these fans run on DC, internally they are ac sysnchronous and thus reversing the DC voltage will NOT reverse the fan. Additional the fan blade shape is designed for a specific high pressure and low pressure side [direction the air will move]. To reverse the fan it must be physically removed and put on in the opposite direction.. Note, most of the fans, have the direction of rotation and direction of air flow molded in the case or marked in some other manner.

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If there is a place in the top
by Ray Harinec / August 22, 2005 3:45 AM PDT

the hole you cut will be round with four holes near it to mount the fan. You then buy and attach a grill with a design of your preference.

Seems that you are paying a good price for aluminum. Beauty is in the eye of the beholder so do YOUR thing. LOL

Many dealers only stock one model, so if there are options make certain that you can get the options already installed in the case. The mfr's site often shows neat options, but getting them can be difficult. I have no fear though because you are doing an excellent job of searching things out.

I think that I already mentioned that the cone mounted to the side could be removed and a fan put in its place. Also mentioned its purpose. I had two similar cases and in both cases removed the cones and replaced them with fans. Still have the cones send them to you if you want them. LOL

If you remove the I?O panel you loose your "front" ports. In my opinion if you you put fans in the available spaces and put a fan in place of the "cup", I wouldn't get into cutting a hole in the top. You should have adequate cooling.

I have a question on your next post. Will reply there.

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Some links
by Ray Harinec / August 21, 2005 11:42 PM PDT
In reply to: Case cooling question

Fans [some with heat sinks] ALWAYS by dual ball bearing type, Do NOT get sleeve bearing types. The ball bearings last much longer.


Here's a Lian Lu with a top exhaust fan. For the Pictures only. Not pushing this case.


Here's a thermaltake, it comes in various colors, not easy to see that it has a top exhaust but it does. The bulge on the top includes the exhaust ports and the frontof thee bulge has the "front" USB/Audio/firewire ports. Beaucoup fans as you will see.


I have an earlier version of this one. Haven't used it yet. It has front contols for each of the fans, a totally unneccessary case. It is heavier than all get out. I bought it without the power supply and still can barely lift it. Can't imagine what it'll weight when it gets loaded.

BTW I recco buying the case without power supply and buying a better supply separately. The PS that comes with the case is usually a lower quality supply in order for price competiton.

Note that if you have time, choose the case you want from newegg and then check every day to see if you can catch it on sale. Usually what they do is slightly raise the price of the case and make it free shipping, but still lower price overall.

Lastly here's a smaller case of the family that I have used many of. Low price. Very simple interior, easy to mount and acess everything. The interior structure may seem flimsy, but who uses their case as a football. Intersting interior structure, have gotten three different mfrs name in which they used the exact samr interior. After I got the extremly heavy server size case, which I have yet to use, I decided that I like lighter cases far better. Of course if you are intending to be a gamer with top level performance, go with the larger case.

Good luck, and when you finally start assembly let us know what you got, and how things worked.

Here's alink to a post that I made regarding assembling a new computer.



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I still don't understand a few things...
by abstraqts / August 24, 2005 11:56 AM PDT
In reply to: Case cooling question

I am probably going to order a Praetorian 730 from Newegg, meaning that I will need to buy an extra 80mm for the back (since there are two places but one fan is included), an extra 80mm for the top and an extra 120mm fan for the side...

Now, exactly what kind of fans will I need? I don't understand the difference between exhaust/intake fans and Newegg doesn't allow me to sort by such specifications. Are they just "fans" and that's it? What kind of fan will I need for the back? For the top? For the side? Someone please explain!

Thank you.

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there is but one
by ninjaforhire / August 24, 2005 3:26 PM PDT

the reason they wont let you specify intake or exaust is because ther is but one type of fan. if you want it to be intake you point it in one dirrection (so the air is moving into your computer) or the other(where air is forced out). as for where to put them the usualy set up is intake in the front bottom of the case and output at the back and top. but hionestly you need to just paly around with it to find out whats bestfor your case. one way to test is to hook up your fans and while the computer is off fill the case with fog from a fog machine through a pci slot or drive bay. then cover the opening and turn on the computer see if the fog moves thgrough well. if some lingers in one place try switching the closest fan to exaust and test it again its trial and error. hope i have answered all your questions.

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Ninja gave intake/exhaust answer
by Ray Harinec / August 24, 2005 10:50 PM PDT

I had included the info about reversing the fans and that the direction of airflow and direction of rotation almost always molded onto the outside of the fan body. Also remember dual ball bearing, no sleeve bearings.

For the side fan, mount it so that it blows air INTO the case.

Are you planning to put a fan on the top??? I was the one that recommended top exhaust, however with that case and the other fans that you will add, I wonder if it is worth hacking up such a nice case for. You are not likely to have a cooling problem.

Remember that the power supply will also have at least one fan exhausting out the rear. The rear fans should exhaust. The side fan should provide lower temp room ambient air to the CPU's HSF, and the front air inlet [opening, not a fan necessarily] will provide adequate flow of air to have the exhaust fans run efficiently. [you need airFLOW, thus if all fans blew in, you would be trying to blow the case up like a balloon and no airflow would occur. If all were exhaust and with no open places for air to come in, same problem, no airflow], so just use logical thinking. Top exhaust is because heat rises naturally and the air in the upper section of the tower is the hottest, and usually an optical device is mounted up high.

I hope that you looked at the assembly tips that I provided a link to.

Good luck and keep us informed as you progress.

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Thank you!
by abstraqts / August 25, 2005 1:47 AM PDT

You all have been very helpful. So no top fan! Thank you!

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One thing that I don't like about these cases
by chuckieu / August 25, 2005 4:12 AM PDT

is they only have the entry over the CPU. Where is a lower one to inject air to the rest of the case? Not counting front entry. The steel case I bought from Newegg
has the CPU cooler entry, complete with a collapsing (adjustable) chute that you move close to CPU, also allowing for 80mm fan between case and chute, if desired.
Another grill-lower- for rest of case. I used 120mm exhaust fan in rear. Power supply has two intake, one exhaust as recommended. Looking at my Motherboard Monitor temps show 48C. CPU, 36C. case. All this for $9.99+ shipping at Newegg. Some would consider this a cheap case, but it does everything it is supposed. A more expensive case with the same featurs wouldn't be a bad thing. FWIW chuck

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Chuckeiu, his has the "chute"
by Ray Harinec / August 25, 2005 4:33 AM PDT

but is replacing it with a 120 MM fan. . I suggested to install the fan so that it blows in, and thus forces fresh room ambient air aroung the HSF. Another fan on the side lower, IMO would be overkill, since heat rises. The lower extremity of the case should really not accumulate any heat.

Do you have an indoor outdoor thermometer with the outdoor a sensor on a cable? If so, put the probe in various locations when fully buttoned up and get a temp profile in the case.
Or do I misunderstand you.

If you followed the thread, there has been some confusion over exactly what the case looked like, photos and descriptions varied. He really won't know until he opens the box. LOL

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by abstraqts / August 25, 2005 4:51 AM PDT

I still haven't decided 100% on the case, but I am probably going for the Praetorian 730. This is my first build ever, so I am going to experiment and see what works. I am planning on ordering by late September, so I still have plenty of time.

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Am I right in assuming...
by abstraqts / August 25, 2005 4:47 AM PDT

Am I right in assuming that the fans in the back, side and front are what Newegg calls "case" fans?

Can I use a fan such as this in the side (I like its airflow and noise level)?

If I want this fan to be intake, how exactly do I position it so it is an intake fan and not an exhaust? Do I flip it to the other side, spin it, etc.?

And what is the difference between sleeve, ball, 1 ball and 1 sleeve and 2 ball bearing?

Thank you. Working soon to buy my new system, so I will keep you posted on everything as soon as I get it.

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Yes, they are called case fans.
by Ray Harinec / August 25, 2005 6:21 AM PDT

You are wise to check on their noise levels, because with the quantities you will be using the system could get fairly noisy. IMO you do NOT need high rpm fans.

As mentioned before, right on the outer body of the fan, there will be small arrows [usually molded and raised], one parallel to the fans major surface, that is the direction that the fan will rotate [you cannot change that]. There will also be an arrow perpendicular to the case that shows the direction of the airflow. [not being nasty, but if you want to have the air flow from outside the case to the inside, you mount the fan so that the arrow points inward]

The side fan is likely to be powered from the standard four pin Molex connectors [the standard things that the Power Supply will have a lot of] so why not buy that fan and have it to look at.

Now, understand that there may be some fans that you would prefer to plug into the connectors on the mobo, for these you must first know if the mobo connector is 2 pin or 3 pin, and buy a fan with the connectors to match. Thus for additional fans wait until you select your mobo, see how many fan connectors it has on it [there will be at least two], one for the CPU/HSF and one noted as system fan [this designation really is not meaningful] to use for the fan of your choice.

The Molex connector is much larger than the 2 pin and 3 pin connectors. The 3 pin on the mobo are from a chip that adjusts the fan speed based on the temperature it detects. The 2 pin adjust the speed similarly, but uses a different method to set the speed.

You can also buy fans that use the large 4 pin Molex, that have a temp sensor on them to detect the temp and control the fan, or a version that has a small variable resistor that you can manually adjust to set the speed.

Youy should go to http://www.cyberguys.com, and get them to send you a catalog, then you'll be able to see pictures of all of these options.

They also sell adapters to adapt any type of fan connector to any other type. They also sell Molex Y cables if you need to add another four pin connector for anything.

Now for the Power Supply, many of them have two fans, both exhaust, you have no choice. Usually the one on the rear that you see from the outside of the case runs directly from 12 volts from inside the PS. The other one is usually a temp controlled one that is intended to plug into a mobo 3 pin connector, so that it only runs when the temp gets above some point.

Keep in mind that all of these fans consume finite amounts of power, thus the power supply has to provide power to all of them. Just building up to not skimping on the wattage rating and quality of the power Supply.

A sleeve bearing [also called a bushing] is simply a piece of Brass or?? with a precise size hole that the shaft of the fan goes through to get supported. The brass will eventually wear enough so that the fan will wobble and have to be replaced.

I have to assume that you know what ball bearings are, roller skates, automobiles etc . The metal ring that the fan shaft goes through for support is ringed by hardened steel ballsfor a full 360 degrees. then there is also an outer ring surrounding the balls. Both the inner ring and outer ring have a "race" with is a hardened steel precision cupped track that keeps the balls in line. With ball bearing the shaft rotation has far less friction and thus less wear, and thus longer life, but alas, they also can fail.

A one ball bearing fan has the shaft supported on one side of the blades only by a ball bearing. Cantilevered but only a virtually zero length cantilever. A tow ball fan has a ball bearing on each side of the blades and is thus a more balanced shaft support.

The bane of the modern computer is that the CPU's now consume so much power, which is all converted to heat and thus the need for fans to keep them cooled. Thus a new reason to have to open computers has evolved. The first was the battery for the CMOS which has a finite life. An all solid state computer could probably run 20 years, be sealed and thrown away when it failed. No more, now one should understand everything that is in the computer, and by building your own you are well on the way to being able to care for your system with ease.

Solid state circuitry has extremely long life many, many years, however fans and other electro mecanical things have much shorter life. Where one could allow earlier computers to run for years, it is not unusual for a newer one to have a fan fail within 2 years.

You'll go nuts selecting the mobo, the CPU, and the Video. The technology chances faster than we can make a decision what to buy.

I cut my teeth on vacuum tube technology, and can really appreciate the fantastic advances. A vacuum tube computer occupied huge rooms and probably failed every couple of hours, thus requiring constant maintenance. LOL

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Thank you!
by abstraqts / August 25, 2005 7:55 AM PDT

I am really impressed by your computer-building knowledge.

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