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Topic Title: CPU fan problem
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Created On: 03/02/2007 06:57 AM
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 03/02/2007 06:57 AM
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gildardo
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Well, I posted this at another site, but since I remembered I was a member here, I decided to post this here, where I am also a member, and since my machine does have a AMD processor, well I realized: where better to ask questions?

OK, my computer is a little over four years old, and regarding temperatures and CPU fan speeds, it has been extremely stable.

First, let me give you some system specs: I have WinXP, sp2; my CPU is a Athlon XP 1800+ mounted on a ASUS A7N266-VM/LAN, memory is 512 000 000 Bytes (note it's not 512MB) of DDR SDRAM. I have a hardware monitoring program, ASUS Probe V2.15.07.

Let me describe my problem:

Some time ago, I noticed that the CPU fan slowed down suddenly, but it recovered slowly after a few minutes -- I would go from close to 5000 rpm to about 4200 rpm essentially instantly and then recover. This seemed to have been caused by dust getting stuck in the fan, since the environment here in El Paso, TX, (where I currently live) is extremely dusty; I just simply blew some air into the CPU heat sink to disperse the dust.

However, another problem started occurring, similar but different in other ways: the CPU started to very slowly spin down, all the way from around 5000 rpm to below 3000 rpm. Another funny thing happened as this was going on: when the CPU fan slowly started spinning down, the motherboard temperature started to DROP too, even though the CPU obviously got hotter; when I'm running a CPU intensive application and the heat sink is clean, the CPU temperature normally would be about 53 degrees C, whereas the motherboard would be 38-39 degrees C, but as the fan's speed went down, the motherboard's temperature slowly dropped a degree or two.

This makes no sense if the sensor is close to the CPU, since the CPU obviously got a few degrees hotter with the slower fan. (I know the CPU temperature sensor is in the Athlon chip, but I have no idea where the sensor for the motherboard is located, despite some googling.)

Well, this later problem occurred once or twice a year ago when the temperature in my room got very cold, and before I realized there was air leaking into the room from the bottom of the door and from other parts. This winter I've insulated these places, and I don't recall this problem ever occurring over the summer. Over the last few weeks however, this started happening a lot more often, especially the last ten days or so, even though the weather has been getting warmer overall.

Since the day before yesterday things got really bad: running a CPU intensive program, the CPU is at 60 degrees C, the motherboard is at an implausible 37 degrees C, and the fan is at a mere 3300 rpm or so (and it is constantly fluctuating), and every once in a while (especially if I'm not running anything important) it dips to below 3000 rpm. If nothing is running, the average fan speed is 3100 rpm, the motherboard temperature is still 36-37 degrees, and the CPU goes down to about 55 degrees C, but the fan has dipped all the way down to 1800 rpm under these conditions.

Now, the CPU fan is not a big fan, and it is supposed to rotate at variable speeds.

What puzzles me the most is the correlation between MB temperature and the fan's spin rate: they both go up and down simultaneously when the problem occurs. And as I said, it's very unlikely that the MB temperature would go down suddenly when there isn't a change in neither the computer workload nor the ambient temperature, but immediately when that happens, sure enough the fan starts spinning slower.

I can't state this strongly enough: my CPU, MB temperature and CPU fan speeds have been essentially rock solid, not varying at all over hours on end of use for most of the last four years, and for the first three years I didn't even think about it --- I didn't even think too much about the CPU and MB temperatures, and the fan ran so smoothly I rarely noticed it. But the last two days I the change is quite noticeable.

Does anyone have any idea what's happening? Is a chip or the fan or the sensor or anything else on the fritz for my computer?
 03/02/2007 08:22 AM
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KachiWachi
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The fan itself could be going bad...or it is just "gummed up".

Do you have a "case fan" as well?

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KachiWachi

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CPU #1 - DFI 586IPVG, K6-2/+ 450 (Cyrix MII 433), 128MB EDO. BIOS patched by Jan Steunebrink.
CPU #2 - Amptron PM-7900 (M520), i200 non-MMX, 128MB EDO
CPU #3 - HP8766C, PIII-667, 768MB SDRAM
CPU #4 - ASUS P3V4X, PIII-733, 256MB SDRAM
CPU #5 - ??? ;)
 03/02/2007 08:44 AM
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gildardo
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Thank you for your reply.

If my fan's gummed up, it is certainly taking its sweet time to get unstuck... and that doesn't explain the odd correlation between the motherboard reported temperatures and the fan speed --- unless the MB temperature is "derived", rather than measured from a sensor.

I will admit the correlation between CPU fan speed and MB temperature is not perfect, but there is no doubt that when the MB temperature is high enough, then the CPU fan "has no complaints", meaning if it gets to about 39 degrees C for at least ten or fifteen minutes and it stays there, then the CPU fan will get back to its essentially noiseless 4900-5000 rpm. But for the last two days if it gets to 38 C it doesn't stay there for more than a couple of minutes --- and even right now it's fluctuating wildly, as the MB sensor reports a temperature of 36 C, even if my CPU reports 62 C. The fan is going back and forth between about 2800 rpm and about 3200 rpm over the course of a minute. This is too slow a rate for the fan, but as variations in speed are concerned: a few days ago even a variation of 100 rpm would rarely occur over the course of ten or more minutes --- I can see almost a second by second variation. (Believe me, when I HEARD any significant change in the pitch of the fan, I always paid attention to what PC Probe told me, and I have never seen this wild behavior before.)

EDIT: I'm sorry: I don't know what you mean by a "case fan". I have a rather simple fan that fits squarely on top of the heat sink.
 03/02/2007 11:16 AM
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MD - Moderator
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quote:

Originally posted by: Unknown
MD's Temperature related standard checklist.

Check the following for overheating or perceived overheating:

- Is the heatsink correctly installed ?
--> Verify it is correctly installed.

- Is the heatsink filled with dust and crud ?
--> Clean with compressed air in a can.

- Is the heatsink fan operating ?
--> Replace defective fan with similar or better unit.

- Is the heatsink adequate for that application/CPU ?
--> Verify it meet the requirements for the CPU being used.
--> RETAIL heatsink? May require lapping and better TIM.

- Is thermal interface material used between heatsink and cpu ?
--> Verify it is used, and is applied according to the manufacturers guidelines.
--> Recommended PCM's, thermal pads from "AMD Thermal, Mechanical,and Chassis Cooling Design Guide #23794.PDF.
- Bergquist HF225UT Phase Change
- Chomerics T725 Phase Change
- Honeywell PCM45 Phase Change
- Power Devices Powerfilm Phase Change
- ShinEtsu PCS-TC-11T-13 Phase Change
- Thermagon T-pcm905C Phase Change
--> Recommended thermal interface material aka: grease, gel etc.
- Arctic Ceramique.
- Arctic Alumina.
- Arctic Silver, 3, 5 etc.

- Is the TIM pad cover removed from heatsink before installation, if using supplied TIM pad ?
--> Remove the cover before installation, failure to do so will insulate the cpu from the heatsink.

- Is there adequate airflow or case ventialation ?
--> Verify airflow, add case fans if required.



- Is the Vcore set higher than specified by the manufacturer ?
--> Verify the Vcore is set to the manufacturers specification in the mainboards bios.

- Is the temperature read via the internal temperature diode. Is the tremperature read via the socket thermistor ?
--> Temperatures read at the diode can and will be higher than an external reading.

- Is the temperature sensor properly calibrated ?
--> Several boards have this problem, check manufacturers bios revision history for calibration fix.
--> Does the heatsink feel warm or HOT, if it's warm it could be a miscalibration error.

- Outside temperature high ?
--> If the external temperature is high, then the case fans will be drawing in hot air, especially during summer months. Remeber, when it's Winter in the Northern Hemi-sphere, it's Summer in the Southern Hemi-sphere & vice-versa.



See the picture, the case fan is the fan that draws air out of the back of the computer case, tower etcetera... Some towers also have a fan that draws air into the case.

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The opinions expressed above do not represent those of Advanced Micro Devices or any of their affiliates.

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 03/02/2007 01:22 PM
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mtrupi
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What motherboard do you have? Can you post a high res picture where the components are identifiable? One possibility is to look for a relatively small 8 pin component sometimes in the area of the north bridge or south bridge chips. Hit it with some canned air and see if the motherboard temp drops a little. That will most likely be your motherboard sensor.
 03/02/2007 08:22 PM
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gildardo
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@MD Willington:

Thanks for the pointers, but I've owned the computer for four years, and the problem I'm describing is fairly recent -- well what I describe has happened on occasion over the last year, but it was rare enough that I could easily ignore it; it's just over the last ten days that it started happening every day, and the CPU fan speed dropped dramatically only a couple of (or maybe three) days ago. And as for maintaining the heat sink free of dust, I'll every now and again will blow some compressed air into the sink to clean it.

My concern is not exactly the overheating, as the processor is not very hot, rather the erratic behavior of both the CPU fan and motherboard temperature: when I see a sudden and very odd drop of a degree in the MB temperature, the fan's spin rate starts to drop, and if the MB drops yet one more degree, then the fan's speed slowly "plummets"; if after a while the MB temperature goes up, the fan speeds up, and if it reaches about 39 degrees C and stays there for a while (this hasn't happened the last few days), then the fan stabilizes at around 4900 rpm. I am concerned not so much that the fan is giving out, but rather that this may be an indication that the motherboard is going on the Fritz.

As for the ambient temperature, as I stated before, I am in El Paso, TX. (In the northern hemisphere so it is still winter -- and I'm not trying to be a smart Alec, just trying to restate what I mentioned before.) The weather did get a bit colder the last few days, and it has been windy, but that has also happened at least a couple of times more this past February, and December and January were much colder, and this erratic behavior of the CPU fan and MB temperature hadn't happened then.

As for the case fan: D'oh! I should have realized what it was. And no, I don't have one -- well, my computer doesn't have one, that is. But that has not been a problem for nearly four years. I'm sorry to insist on this: the problem is a recent one in an otherwise mostly flawless performance of my computer.

@mtrupi:

My motherboard is a ASUS A7N266-VM/LAN, as I said before (I think). Thank you about the suggestion on where to find the motherboard's temperature sensor, and if I find a good picture of it I'll include it here.

And to everyone: thanks for any replies, whether already posted or for future ones.

EDIT: this is the best image I could find of my motherboard -- it's only 400x412 pixels in size, hope this is enough.

 03/03/2007 01:14 AM
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tazwegion
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I'm sorry to be blunt, but allowing your CPU fan to run between 2800 ~ 5200 is playing with fire, personally I'd be replacing it yesterday then there will be plenty of time to contemplate CPU fan RPM & MB temperature correlations

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 03/03/2007 02:39 AM
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gildardo
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I've been paying attention to what I'm being told here, at another forum, searching google, and I guess the best thing to do would definitely be to replace the fan, as tazwegion so bluntly states. My problem is I can't buy one right now, as the only card I have (a debit card) was stolen, and I have no cash at the time. I hope the replacement arrives soon.

So, as I am broke for now, I guess I will have to get by on a cheap one -- heck I just saw one for around $3.50 US DLS.

So, what should I buy beside the fan? Some thermal paste? Is anything that's recommended for my cpu available at an electronic store?

EDIT:

Well, I've doing a Google search, and I've found a few rather cheap fan and heatsink combos. However, I have to ask, does the heatsink have to have the square of "phase change thermal interface material" or can it be something else? I've seen a few that say their "thermal type" is "white grease" which is usually pre-applied. Is this good enough?

The vendor also states that the several models can be used on Athlon XPs: would there be a problem if it says it can be used on an Athlon XP 3200+ or an Athlon XP 2100+ as opposed to my Athlon XP 1800+?

Thanks for any further replies.
 03/03/2007 07:29 AM
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KachiWachi
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For the moment, you don't have to buy anything.

With the PC turned off and "open", see if you can turn the CPU fan with a finger.

It should turn easily and freely.

If not, you can try to clean and oil it while you are waiting to buy a replacement.

To oil the fan, you need to remove the sticker and pull the plug behind it. Then put a small drop of light oil on the pin. Spin the fan by hand until it frees up. Then reinstall the thing...see what happens.

Thanks.

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KachiWachi

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CPU #1 - DFI 586IPVG, K6-2/+ 450 (Cyrix MII 433), 128MB EDO. BIOS patched by Jan Steunebrink.
CPU #2 - Amptron PM-7900 (M520), i200 non-MMX, 128MB EDO
CPU #3 - HP8766C, PIII-667, 768MB SDRAM
CPU #4 - ASUS P3V4X, PIII-733, 256MB SDRAM
CPU #5 - ??? ;)
 03/03/2007 07:51 PM
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gildardo
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Thank you for the suggestion, KachiWachi. The fan does turn with relative ease, so it doesn't seem to be stuck, but maybe a tiny bit of lubrication may still help. Maybe.
 03/03/2007 09:30 PM
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mtrupi
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quote:

Originally posted by: gildardo
@mtrupi:

My motherboard is a ASUS A7N266-VM/LAN, as I said before (I think). Thank you about the suggestion on where to find the motherboard's temperature sensor, and if I find a good picture of it I'll include it here.



I had one of those up until a few months ago when it literally went up in smoke. I never bothered to try to and figure out the motherboard sensor location. However, in the lower left corner you will see an LM78 which is probably the motherboard temp sensor.
 03/04/2007 02:07 AM
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gildardo
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Thanks again, mtrupi, and sorry to hear about your motherboard. Mine, on the other hand, has given me good service.

As for KachiWachi's suggestion about how to lubricate the motor: well, I removed the AMD sticker at the center of the fan, but couldn't really see a plug, so I cannot add any oil to it. But in any case, without any power the fan can turn fairly easily, so if some dust has stuck to it and added any extra resistance, I cannot tell.

I have to say that the first time I noticed the fan doing something funny was about a year ago, when I added a second hard drive: I had a 40 GB Seagate, but then added a second one -- a 160 GB drive from Western Digital. After I added the drive and turned on the computer, the fan's spin rate dropped from the usual 4900 rpm to about 3800. I turned off the computer and disconnected the new drive, and sure enough the spin rate was normal when the computer was on again. I connected the drive again, and the fan's rate dropped once more. This time I let the computer on for a while, and within the hour the fan had gone back to its typical spin rate. With the problems that I've been having with the fan, I remembered that -- I hadn't given it any importance until now.

But anyway, I am convinced it's the fan, not anything else that's failing: the voltages PC Probe reports are fine (The Vcore is 1.8V, and the other voltages are off by less than 1%), and the temperatures have been holding steady. I am, however, running the computer now with one panel open, and that somehow boosted the speed of the fan a little bit (I guess it changed the airflow inside the computer). I am keeping an eye on dust, and as soon as I can buy a new fan I'm putting the panel back on.
 03/04/2007 08:29 AM
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KachiWachi
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It sounds like your Power Supply is marginal then.

It may still be regulating the voltage properly, but it cannot supply the current demands of the system when the additional HDD is installed.

HDD use both 5 and 12 Volts...so you need to see which the fan is using...and go from there.

Thanks.

-------------------------
KachiWachi

Moderator - Wim's BIOS

CPU #1 - DFI 586IPVG, K6-2/+ 450 (Cyrix MII 433), 128MB EDO. BIOS patched by Jan Steunebrink.
CPU #2 - Amptron PM-7900 (M520), i200 non-MMX, 128MB EDO
CPU #3 - HP8766C, PIII-667, 768MB SDRAM
CPU #4 - ASUS P3V4X, PIII-733, 256MB SDRAM
CPU #5 - ??? ;)
 03/04/2007 05:23 PM
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Suzueya
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Since the fan plugs into the mobo, and is of the varieable speed variety, (speed increasing or decreasing depending upon temp), and since its speed seems to move in lockstep w/ the temps reported by the mobo, the obvious question is : Is it plugged into the chassis fan riser by mistake?
 03/04/2007 07:56 PM
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gildardo
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quote:

Originally posted by: Suzueya
Since the fan plugs into the mobo, and is of the varieable speed variety, (speed increasing or decreasing depending upon temp), and since its speed seems to move in lockstep w/ the temps reported by the mobo, the obvious question is : Is it plugged into the chassis fan riser by mistake?


No, it's definitely connected into the correct place -- it is clearly marked CPU fan on the MoBo.

I have considered that the power source may not be cutting it, but since the fan has just not been behaving the way it has for the great majority of the last 4+ years, I am now also convinced that the fan has reached the end of its life. I will have to take into account the current/power consumption of the new fan. Eventually I will probably also buy a new power supply, but maybe by then I will have enough money to just simply buy a new system.

Again, thanks for all the replies.
 03/07/2007 03:37 AM
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gildardo
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I hope someone will still read this topic of mine.

From somewhere else I got the suggestion of disconnecting the "speed" wire from the MoBo: the result is that the fan is running at least very stable -- from the pitch it emits, I can tell it's still running at least 1500 rpm slower than its typical 4900, but it at least stopped fluctuating -- at least for a few hours at a time, since after a few hours it seems it starts slowing down gradually.

Anyhow, I found a fan that I like from this company called Masscool. Has anyone heard of this company? Are their products any good? The fan's specs imply it's relatively quiet (26.5 dBA), although it is a bit heavy (one pound), which makes me wonder if it's too heavy for my tower arrangement. Does anyone have an opinion?
 03/07/2007 10:14 AM
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mtrupi
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quote:

Originally posted by: gildardo
I hope someone will still read this topic of mine.

From somewhere else I got the suggestion of disconnecting the "speed" wire from the MoBo: the result is that the fan is running at least very stable -- from the pitch it emits, I can tell it's still running at least 1500 rpm slower than its typical 4900, but it at least stopped fluctuating -- at least for a few hours at a time, since after a few hours it seems it starts slowing down gradually.

Anyhow, I found a fan that I like from this company called Masscool. Has anyone heard of this company? Are their products any good? The fan's specs imply it's relatively quiet (26.5 dBA), although it is a bit heavy (one pound), which makes me wonder if it's too heavy for my tower arrangement. Does anyone have an opinion?



The speed wire in your case does nothing to help control fan speed. It is only monitored. The possibilities are the fan, the power supply, or the motherboard are failing. That assumes everything is assembled correctly. This also includes connectors. Have they been plugged and unplugged too many times. Sometimes it doesn't take much. Sometimes they were always marginal and you just didn't have any symptoms until now.

I bought a Masscool USB/firewire card. It worked fine. I can't say much else about that.
 03/07/2007 11:13 PM
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gildardo
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Well, certainly the "speed" wire doesn't control the fan, but it does provide the feedback to the system in case of a variable speed thing --- which seems to be my case. Anyway, what I was told was that without the "knowledge" of the fan's speed, the system would just simply have it pump at its maximum rate, which seems to be the case now. And as for the fan being disconnected, I had never done that, for the 4+ years I've had my system, which was custom made and bought brand new.

Thanks for your comments on your Masscool card, mtrupi --- it gives me a little bit more of confidence concerning their products.

But anyway, considering my system is a tower, would a 1 lb (454 grams) fan be too heavy? I know have the space to put it in, I just don't want it to come off the CPU all of a sudden...
 03/08/2007 01:15 AM
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mtrupi
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quote:

Originally posted by: gildardo
Well, certainly the "speed" wire doesn't control the fan, but it does provide the feedback to the system in case of a variable speed thing --- which seems to be my case.

But anyway, considering my system is a tower, would a 1 lb (454 grams) fan be too heavy? I know have the space to put it in, I just don't want it to come off the CPU all of a sudden...



The A7N266-VM does not have fan speed control.

The heat sink is probably fine if it was made for socket A cpu's. Maybe I misread but I don't see where you say what model you are considering.
 03/08/2007 04:04 AM
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gildardo
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quote:

Originally posted by: mtrupi
The A7N266-VM does not have fan speed control.

The heat sink is probably fine if it was made for socket A cpu's. Maybe I misread but I don't see where you say what model you are considering.


Oh, wow, that makes the fan's behavior even more puzzling... /blink.gif" style="vertical-align:middle" emoid=":blink:" border="0" alt="blink.gif" /> I was under the impression my MoBo had some amount of control of the fan. Oh well, I'm getting a new one in any case, so if that one doesn't work, then I'm probably in real trouble.

I hadn't mentioned which model of fan I was considering; it's the Masscool 5F263B1M3G (about US $7.50), though the 5F522B1M3CG (about US $15.00) also caught my eye, even if it's twice the price and a little heavier. Both seem quiet, and also their airflow seems pretty decent, by comparison to others. I found them doing a Google search on "cpu fan", the company I'm looking at is gogofan.com.

Thanks for the reply, mtrupi.

EDIT: corrected a sentence.
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