where to use external fan?

[tomtomg59]

Hello, everyone: I use my pc for hours on end and its hot in filthydelphia right now, so i got a small 4 inch fan and placed it directly in back of my tower facing the internal fan in pc! Now i thought that would help keep it a little cooler, but i noticed it seems to be hotter not cooler, so i took the little fan away, now i just use a big fan on high and let the air bounce off the wall and on to the pc and this seems to be better! I guess when i put the little fan directly facing the internal fan, i must have been sending heat into the pc? Does anyone know if this is true and where should i place the little fan or do i need it at all? Any suggestions on this and how to keep my pc cooler, please let me know, Tom

[mjc]

Well, what kind of temps are we talking about?

Are you doing this with the case openned or closed?

The cases are designed to be closed and use the internal fans to move the air around...you are probably correct that you were forcing the hot air back into the case with that small external fan, had you turned it around to pull the air away from the computer you may have seen an improvement.

If you are having heat related problems (crashes and lockups that occur and reoccur until the case temp drops....) then you may want to look into redesigning the cooling system of the case. Too many internal fans can cause as many problems as not enough. Basically you need either enough vent space or a fan to pull cool air into the front of the case (this one should be low) and one to exhaust the heated air out the back (this one should be high). Unobstructed vent space is very important, if your case has side vents, they should be free and clear and at least a couple of inches from a wall.

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mjc
Links list:Computer Links (http://www.dreamwater.org/tech/mjc/index.htm)

Celts are the men that heaven made mad, For all their battles are merry and their songs are all sad.


[This message has been edited by mjc (edited 04-19-2002).]

[tomtomg59]

mjc: I am not having any problems at all that are heat related, i just want to make sure this pc stays cool, i use it over 6 hours a day and its hot right now, my house AC is broke! Of Course last year i had no problems with my old pc, so maybe i will be ok, Paranoia is setting in! A friend told me exactly what you said, and that is to turn the fan around and draw the heat out. If i put a fan directly in front of the tower to, would that force some hot air out? I always leave my covers on, i heard it is not good to run a computer with the case off!

[ski]

There's nothing wrong with running a computer with the case cover removed.
In fact it may reduce your system's temperatures. Just keep prying fingers and animals from wandering into its innards.
I do not have a/c, and during the recent hot spell up here in Wilkes-Barre I found that removing the case cover reduced the CPU's temp by a few degrees C. and blowing air onto it with an external fan reduced the temp a little more.

[Rick]

I agree with MJC keep the case closed and install an extra fan or 2 IF needed.

I also believe it is best to use exhaust fans to rid the case of heat and Not blow air into them IF you have the fans setup correctly and adequate intake vents/ports

In a few cases where you have 2 exhaust fans and 1 intake fan the intake fan will actually reduce air flow


During the past week and the unexpected temps.
I also noticed a temp raise in my system .
The cure ! Preform the DnC ( Dusting and Cleaning) on the system case and fans
Clearing out any and all Dust Bunnies from the vents and fans.
Dropped temps back to within normal range

I should also note that the only time I run a case open is while working on it.
I also place a small 4 inch fan blowing indirectly into the case .
Not directly onto the M/B or cpu. But placing it so it blows first onto the drives and allow the case fans to draw the air across the M/B and out of the case

[tomtomg59]

Ski, You might want to take a look at this, maybe you are not aware of this>> http://www.pcguide.com/care/care/gen/cool.htm

[ski]

Thanks for the cooling link, tomtomg59.
But actually I've already read the cooling info from that site as well as from many others, and I am fully aware of the different methods for cooling down a computer, including removing the case.

This will give you and others some insight as to why I removed the cover and ran an external fan to cool things down last week, instead of using the recommended "keep-the-cover on" method.
Prior to finishing an upgrade(Abit KR7A-133, Athlon XP 1800+, Geforce4 TI 4400, 256MB PC100, and an Enermax 430W PSM) the week before last, my original system always ran fine without any overheating problems(Always kept it clean and dust free too).
After the upgrade was completed, I knew that everything would run hotter and that the case and CPU temps would increase more than previously. But I wanted to see exactly how high the temps would go when the ambient temp got into the 80's with the current ventilation setup, since it already involved 6 fans(2 in the PSM, CPU, video card, MB northbridge chipset, and lower front case) and I did not want to install any more fans and increase the overall decibel level if possible.
With the cover installed, the ambient temp hovering around 90 deg. F, and after playing a few hours of Combat Flight Simulator at 1600x1200 with antialiasing set at 4X and all of the game graphics maxed out, the CPU temp rose to 58 deg. C.
Although this temp was not excessive and there were no problems(crashes, lockups, etc.), I felt that this temp would not contribute to a long CPU life, especially if it operated at that temp for prolonged periods(I play CFS 2 a lot year round). So not having any time to utilize other cooling options, off came the cover, on went the external fan, and down came the CPU temp to 52 deg C within a minute or two. Now I felt more comfortable. And guess what? No problems were encountered running the computer with the cover off!
But since it's a pain in the butt to constantly remove the case every time the ambient gets a little toasty(and replace it every time my grandchildren visit), I do not view running the computer with its case removed as a long term solution.
Fortunately, I have some options at my disposal which I can incorporate into my system down the road, including installing a higher capacity CPU fan, an upper rear case fan, and/or a higher capacity lower front case fan(hate to introduce more noise but may have no alternative, other than to install a water cooler or perhaps liquid nitrogen like they did on Screensavers), drilling additional and/or larger ventilitation holes in the case, buying a new case, etc.
But if the temps get back into the 80's or 90's before I have a chance to put any of these options into play, I will not hesitate at all to remove the cover and plug in the external fan again.

[tomtomg59]

Ski, Thank You Very Much for that lesson, i believe every word because there is nothing like on hand experience. Some times you just cannot go by the book in life! I always listen when someone has been thru something and i pay attention, who knows i might need to do the same thing one day. Thanks again, Tom