Dumb question: CPU cooling fan

[Buccaneer]

Dumb question.

Should the CPU cooling fan on the heatsink be blowing air into the heatsink or out of the heatsink?

[finkenst]

yes

[Buccaneer]

That's what I've been reading. I have instability problems coming from overheating (allegedly) and I am having a hard time finding the source.

[AgPete]

Are you overclocking your system?

[Buccaneer]

No.

[finkenst]

do you have the case on?

[Buccaneer]

Ok, I'll be more specific. I am building my own system. I have an Antec 350w case, Asus A7V8X-X mb, AMD 2200+ CPU, GeForce FX 5200 AGP and (2) single-banks PC3200 DDR400 256mb SDRAM. Ever since I installed all of the component, I can't get beyond POST - it just gives me a blank screen and 4 beeps. No matter what I have tried - all I get is 4 beeps.

I got a reply from Asus this morning and they have me a huge list of complicated things to try. Basically, the message was "The problem you are reporting is a stability issue and is usually caused by either the memory, power supply or the CPU running too hot. Pleasecheck with the memory maker to see if the module you are using has been
tested or certified with the chipset on your motherboard. Also, check
that your power supply can supply enough power for your system
configuration and that your CPU's heatsink and fan are properly installed.
First, please check that your CPU is not overheating. You can check this
in the BIOS setup, under Power, then Hardware Monitor. If the CPU is
overheating, please check that your heatsink and fan are properly
installed and that you are using exactly one heat transfer agent between
the CPU and heatsink (ex. Artic Silver). Make sure that the heatsink
compound is applied ONLY to the CPU die and that it is NOT shorting any
surface mount components on top of the CPU or contacting the CPU's pins.
Please check http://www.asus.com/support/cpusupport/cpusupport.aspx (http://www.asus.com/support/cpusupport/cpusupport.aspx) to
verify that your board will properly support the CPU that you have. This
link will list the minimum BIOS and PCB version that you must have to
PROPERLY support your CPU."

I am monitoring the MB and CPU temperature and they are running 26C and 38C, so those are fine. I have (3) 80mm fans running (two in front, one in back) and the power supply fan is running fine.

Any ideas?

[Craptacular]

I think it's usually common sense. Don't have fans that fight each other or work in opposite directions. If your fans on the front are blowing in, then your fans on the back should be blowing out.

[Buccaneer]

They are, hence the 'cool' MB temperature.

[MizzouRah]

Never really thought much about it... and I'm a technician. :) I always make sure I can see the sticker in the center of the fan. Meaning: The fan should be pulling the heat away from the Processor. (with it spinning, you should feel air)


Todd

[AgPete]

I read once that you built your own computers. Have you tried troubleshooting and installing different hardware components to see if one of your parts is causing the problem to begin with? Other than that, I'd check the shorting recommendations because I've had weird accidental startup probs myself from that when building a system.

[Craptacular]

Well then I wouldn't worry about overheating. :) Are the four beeps all the same length??

[Buccaneer]

Todd, from what I have read, the fan is not actually blowing air into the heatsink but around it so it can go under the CPU (without a duct shield of course). The most stable CPU temperature is 40c to 45c and after 20 minutes, that exactly what it is sitting at (idle). It can go up to 65c.

[Buccaneer]

Well then I wouldn't worry about overheating. :) Are the four beeps all the same length??
Yes.

[Buccaneer]

I read once that you built your own computers. Have you tried troubleshooting and installing different hardware components to see if one of your parts is causing the problem to begin with? Other than that, I'd check the shorting recommendations because I've had weird accidental startup probs myself from that when building a system.
Thanks, that's on my list for tomorrow night.

[Craptacular]

Beeps: long or short?

[MizzouRah]

Todd, from what I have read, the fan is not actually blowing air into the heatsink but around it so it can go under the CPU (without a duct shield of course). The most stable CPU temperature is 40c to 45c and after 20 minutes, that exactly what it is sitting at (idle). It can go up to 65c.Well, on Compaq and HP prducts, the CPU fan pulls the air AWAY from the heatsink. (at least I'm 90% sure) The heatsink soaks up heat from the processor and the fan pulls it out of the heatsink, if it was blowing inward, it would keep the heat in. Might be different in your system though.

I would try removing everything and then adding things one at a time until you get the beeps. I suspect one of your memory modules are bad. Try one, power up, if it doesn't post, remove and try the other (memory). I really don't think it's a heat problem.

[jeff061]

Generally, air should be blowing into the heatsink.

[AgPete]

My advice is to ignore the overheating debate. I know where you're coming from. LOL I've had the same frustration. You put together this new computer only to be confronted with frustrating issues and you start thinking about any issues that could be causing the problem. I doubt it's overheating, just troubleshoot with your old hardware and make sure you didn't accidentally install something the wrong way. (Which includes shorting.) 99% of the time, I find that solves or at least identifies any problems I'm facing.

[Craptacular]

I'd check your beep code. For an AMI BIOS, 4 short beeps means a system timer failure:
"The system clock/timer IC has failed or there is a memory error in the first bank of memory"

http://bioscentral.com/beepcodes/amibeep.htm

[Airhog]

my machine regularly gets up between 50-60c so your definately not having an overheating issue.

[Fonzie]

I was always under the impression that the CPU fan should be blowing onto the CPU/heatsink.

[Sun Tzu]

Yes the CPU fan should be blowing air into/towards the CPU itself.

I don't envy you Bucc, this one sounds like a nightmare. That's the problem with building PC's sometimes. You never know when one of the components will just randomly work incorrectly. Sometimes everything just clicks and flows perfectly, and sometimes it's just one thing after another. Best of luck bud.

[Draft Dodger]

I doubt it's a heat issue, especially if you are getting it from word go.

I too think it might be memory.

[Samdari]

I think that the fan is supposed to blow away from the heatsink. I buy midrange third party coolers, and they come with the fan attached to the heatsink. Every one of these I have bought have the fan blowing away.

[Buccaneer]

Thank you all for your help. As far as the HSF, this particular model supposed to blow onto the CPU. Other models can do different things.

Crap: I have an Award BIOS and they only have one beep sequence.

I think I may have finally found the problem. According to the BIOS Hardware Monitor, I noticed that the CHASSIS Fan Speed was highlighted in red. I didn't know what that meant. A little digging around on this Antec power supply shows that the RPM range supposed to be 1200-2500rpm. Mine was running at a constant 1028rpm. This was why it was highlighted in red and may be the cause of the instability (if so, it really was an overheating problem). Tomorrow, I will replace this 350w with a 400w (since that is recommended for systems with an AGP card) and hopefully I can get the RPM up.

[AgPete]

Thank you all for your help. As far as the HSF, this particular model supposed to blow onto the CPU. Other models can do different things.

Crap: I have an Award BIOS and they only have one beep sequence.

I think I may have finally found the problem. According to the BIOS Hardware Monitor, I noticed that the CHASSIS Fan Speed was highlighted in red. I didn't know what that meant. A little digging around on this Antec power supply shows that the RPM range supposed to be 1200-2500rpm. Mine was running at a constant 1028rpm. This was why it was highlighted in red and may be the cause of the instability (if so, it really was an overheating problem). Tomorrow, I will replace this 350w with a 400w (since that is recommended for systems with an AGP card) and hopefully I can get the RPM up.

Good luck! I know the frustration you're going through. All that new hardware and the damn thing won't run! Grrrr. Computers are pretty easy to build but when they have a problem, it can be a %#*$# to find out what it is.

[Maple Leafs]

Bump... (rather than start a new topic).

I know very little about hardware even at a basic level like this, so please explain it to me like I'm a Canadian.

My fan appears to be dead. My cpu seems to be running hot, and the fan is nowhere to be seen... er, heard. It had been getting progressively louder over the weeks, but now it doesn't seem to be running.

The CPU is warm/hot to the touch in the back and there's even a slight smell (like dust on a heated surface). I installed a temperature monitor and it's showing two readings -- temp 1 at 37 degrees, temp 2 at 53. From what I know that's high but not alarmingly high. System is running fine, no shutdowns or slowdowns. No performance issues at all right now.

Should I worry about this? Is a fan something that can be fixed/replaced myself, or will I need to get someone to do it for me?

[Buccaneer]

Those temps seem ok (they're in C). My recommendation is go to your nearest computer store and get a CPU fan. It uses 4 small screws to go on top of the CPU heatsink unit (all those vertical metal stuff). I am not sure if one size fits all, though. Good luck, just don't let a potential problem get worse.

[Mr. Wednesday]

Hmm... Offhand, I'd think that blowing air onto the heatsink would get you better airflow (and possibly a better temperature distribution as well), but I'm not sure. Higher velocity air and a more favorable temperature distribution (i.e. maximization of low temperature air on the hot parts of the heat sink) would, I think, maximize heat transfer... but it's been nearly ten years since I took heat transfer and I don't think we really looked at problems like this (we were more focused on being able to model industrial heat exchangers).

[Airhog]

Sounds to me like you just need a bigger powersupply

[Airhog]

I would think it would matter wether it is blowing or sucking, since the general idea is just to get the air moving across the fins. It seems to me that blowing the air, would push more air across the fins at a higher speed.

[TargetPractice6]

Hmm... Offhand, I'd think that blowing air onto the heatsink would get you better airflow (and possibly a better temperature distribution as well), but I'm not sure. Higher velocity air and a more favorable temperature distribution (i.e. maximization of low temperature air on the hot parts of the heat sink) would, I think, maximize heat transfer... but it's been nearly ten years since I took heat transfer and I don't think we really looked at problems like this (we were more focused on being able to model industrial heat exchangers).That's what I was thinking. I know for sure that my fan blows onto the heat sink. The idea isn't to pull the hot air away for the CPU. You want to blow cool air across the fins of the heatsink.

[Mr. Wednesday]

The idea isn't to move air in any particular direction (that's what your case fans are for), the idea is to maximize heat transfer away from the heat sink. :)

[Rizon]

Dude, just take all the fans out of your computer and do what my younger brother did:

http://home.comcast.net/~rizon1976/Image442.jpg

(his computer lived for a week after he did this)

[Mr. Wednesday]

Nah, get hard core. Submerge it in mineral oil. :D

[Neon_Chaos]

Dumb question.

Should the CPU cooling fan on the heatsink be blowing air into the heatsink or out of the heatsink?

It should be blowing air AWAY from the heatsink.

[TargetPractice6]

It should be blowing air AWAY from the heatsink.No, it should be blowing on the heatsink.

[sterlingice]

Those temps seem ok (they're in C). My recommendation is go to your nearest computer store and get a CPU fan. It uses 4 small screws to go on top of the CPU heatsink unit (all those vertical metal stuff). I am not sure if one size fits all, though. Good luck, just don't let a potential problem get worse.
Or just unscrew the non-working fan and bring it in with you.

This made me dig up the ASUS diagnostic on my board. I love this new setup. I'm running at 43/36 even after leaving it on overnight (d'oh) on an Athlon64 2800.

SI

[MizzouRah]

Definitly replace the fan with one similar. They are there for a reason. That or be prepared to buy a new processor.


Todd

[jeff061]

It should be blowing into the heat sink, not away.

Repeated I know. I suppose ultimatley it may depend on the type of heatsink. Everyone I ever used air needed to be blown in, per the directions.

[Maple Leafs]

Definitly replace the fan with one similar. They are there for a reason. That or be prepared to buy a new processor.Thanks all.

Is it just as simple as unscrewing the dead fan, getting a similar one and screwing it back in?

[Buccaneer]

Yep (and getting the fan's power cord connected into the same slot you took the old one out of).

SI: That's what I ran last night to see my numbers (the ASUS Probe Utility). Nice little tool.

[Mr. Wednesday]

Measure the fan -- they come in different sizes, typically in mm (e.g. 80 mm).

(or you could take it with you, as previously suggested... :p)