help hooking up new cpu fan

  • Thread starter Thread starter Lily
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Lily

My computer came with a tiny no-name cpu fan and heatsink. With summer
coming, the cpu running at 64C is probably not a good idea. I couldn't
remove the heatsink, so all I can do is change the fan. I've narrowed
it down to 2:

1) Zalman FB123-92mm Fan with adjustable bracket
This kinda hangs on the bracket in front of the heatsink. It seems
pretty cool, but I don't know if the fan that came with it is powerful
enough.
2) Thermaltake Smart Fan II w/ temp. sensor control
At max speed, i think this fan is a lot more powerful than the Zalman.
This one is 80mm though, and my heatsink is designed for 60mm, so I'd
have to use some wires. (if anyone know a better way, tell me, and I
don't want to spend $20 on a bracket for a $20 fan!) Don't really need
the temp. sensor, since I don't plan on taking off the heatsink.

So, any suggestions? Is it very important for the fan to be very close
to the heatsink?
Oh, and, what would you use to cut a computer case? Is it worth the
trouble?
 
" I couldn't remove the heatsink, so all I can do is change the fan. "


Is it the clip, or is it still stuck with the clip removed? They might have
used a sticky thermal pad. What CPU is it? Socket-A Athlon?
 
My computer came with a tiny no-name cpu fan and heatsink. With summer
coming, the cpu running at 64C is probably not a good idea. I couldn't
remove the heatsink, so all I can do is change the fan. I've narrowed
it down to 2:
Click to expand...

As Cuzman suggested, investigate why you can't get heatsink off...
replacing the heatsink itself is by far the best solution but I'll address
the rest of the post anyway.

1) Zalman FB123-92mm Fan with adjustable bracket
This kinda hangs on the bracket in front of the heatsink. It seems
pretty cool, but I don't know if the fan that came with it is powerful
enough.
Click to expand...

A bracketed fan is used more for supplimentary cooling of items like
overclocked video card or Zalman's passive coolers (or other coolers
designed to be passively cooled). It is very likely to result in higher
temps than your present fan, but used in conjunction WITH the present fan
still installed it might lower CPU temp a couple degrees, moreso if your
power supply doesn't have an air intake on the bottom so that there were
dead spots of air being recycled though the heatsink fan.

2) Thermaltake Smart Fan II w/ temp. sensor control
At max speed, i think this fan is a lot more powerful than the Zalman.
Click to expand...

If you're only considering max cooling potential from max speed, there is
no point in getting the "smart fan" or any other with thermal sensors.
Actually one with ONLY a thermal sensor must have that thermal sensor
located such that it gets fairly hot else the fan spins slowly.
This one is 80mm though, and my heatsink is designed for 60mm, so I'd
have to use some wires. (if anyone know a better way, tell me, and I
don't want to spend $20 on a bracket for a $20 fan!) Don't really need
the temp. sensor, since I don't plan on taking off the heatsink.
Click to expand...

There are fan adapters, more-or-less a plastic funnel with screw holes, to
adapt 80mm fan to 60mm heatsink's fan mount, but it's a poor alternative
to a better heatsink that is designed to use 80mm fan. Generally these
smaller 'sinks that take 60mm fans won't cool much better with an 80mm fan
on top, it would only be a bit quieter.

Wires can work though, there are several ways to adapt a fan.
So, any suggestions? Is it very important for the fan to be very close
to the heatsink?
Click to expand...

Yes, it's very, very important.
You didn't tell us much about this system though, like the CPU
make/model/speed, and highest ambient (room) temp expected. Was the 64
temp what you saw last summer or just a guesstimation, and was that 64C at
idle or full load or somewhere inbetween?
Oh, and, what would you use to cut a computer case? Is it worth the
trouble?
Click to expand...

Depends on what you're cutting, what case, how thick the metal is, and
where on the case.

If the case has inadequate airflow, you need do some cutting or replace
the case, assuming you've used all available fan mounts. Cutting out
stamped-in-metal fan grills can help a lot too.

Thin walled metal is easier cut with tin snips or a nibbler. Nibbler is
better. Thicker metal can be cut with nibbler (depending on how good the
nibbler and how thick the metal) or a sabre saw. Fan grills can be cut
out with tin snips still, they'll do the job but you'd have rough edges...
perfectly functional but less esthetically pleasing. Round holes can be
cut with a hole saw but that's easier with a solid piece of metal, not
cutting a hole where there's already cuts in the metal (like a stamped fan
mount).

We can only assume based on your question that you need to start
cutting... if the case definitely needs airflow increase then you might
consider doing that first and see how the modification effects CPU temp
before deciding on a CPU fan/heatsink.
 
Thanks for your responses!

I'm using AMD Thunderbird 1.33 cpu.
The temperature in my room is about 20C. After a couple of hours, the
cpu will always get above 60C/140F. I've seen it get to 64C recently,
and during the hottest days, it takes a few seconds to click a button.
If I leave the computer case off, it's 2 or 3 degrees cooler.
My last power supply broke and I bought a new one this year with 2
fans, sucking air out. This made absolutely no difference in the
temperature. I borrowed an 80mm fan and put it so that it sucks air
out of the case, this made about a 3 degree difference for the case
temp but no difference for cpu. So you see why I want to change the
cpu fan.

I'm not sure how un clip the heatsink. It's kind of blocked, I can't
see much and my finger can't really get in there. I'd rather not try
to take it off unless it's a last resort, it seems to be a lot of
trouble and a bit risky since I've never done it before.

I'd be happy if my cpu temp is in the 50s. Any help will be
appreciated!
 
4On 21 May 2004 14:45:51 -0700, (e-mail address removed) (Lily)
wrote:
Thanks for your responses!

I'm using AMD Thunderbird 1.33 cpu.
The temperature in my room is about 20C. After a couple of hours, the
cpu will always get above 60C/140F. I've seen it get to 64C recently,
and during the hottest days, it takes a few seconds to click a button.
Click to expand...

I don't understand "click a button".
64C is borderline. If your present heatsink is the AMD retail heatsink
that came with the CPU, you might reduce temp by 5 degrees or so by simply
removing heatsink, scraping off original thermal interface material with a
credit card and some petroleum solvent, then applying a thin coat of
thermal compound. 5 degrees could be enough... typically a CPU at stock
speed is stable at 60C, but approaching 70C it's borderline, particularly
so with higher speed CPUs of a given family, like your T'Brid @ 1.3GHz,
those T'Birds only went up to 1.4GHz if I remember correctly.
If I leave the computer case off, it's 2 or 3 degrees cooler.
Click to expand...

2-3 degrees isn't much of a difference, if your CPU were cooler than 60C
I'd speculate that the case cooling was adequate, providing other parts
like hard drive and video card also remained cool enough. However, given
the higher temp of CPU there is a larger difference between heated case
air and CPU temp, so it's a tough call whether the case needs anything
more done. That is, without seeing it, whether there is amply air intake
passages and exhaust flow rate you'll have to determine that for yourself.
My last power supply broke and I bought a new one this year with 2
fans, sucking air out. This made absolutely no difference in the
temperature. I borrowed an 80mm fan and put it so that it sucks air
out of the case, this made about a 3 degree difference for the case
temp but no difference for cpu. So you see why I want to change the
cpu fan.
Click to expand...

Yes, it does seem the heatsink + fan is a problem, but the most likley
solution is still replacing whole heatsink. The present heatsink is
physically smaller ignoring the fan, so any fan you use will still result
in less effective cooling than similar but larger heatsink, or
preferribly, a 'sink with an all-copper bottom. Then again, I'm still
assuming you have the retail 'sink.
I'm not sure how un clip the heatsink. It's kind of blocked, I can't
see much and my finger can't really get in there. I'd rather not try
to take it off unless it's a last resort, it seems to be a lot of
trouble and a bit risky since I've never done it before.

I'd be happy if my cpu temp is in the 50s. Any help will be
appreciated!
Click to expand...

Well there are a bunch of high-flow 60-80mm fans out there, but of course
there's a pretty direct correlation between airflow, RPM, and noise...
some of the higher airflow fans sound a bit like a hairdryer.

There's a selection of several 60 to 80mm adapters here:

http://www.svcompucycle.com/fanad80to60.html

Panaflo makes fans with some of the best airflow to noise ratios, are more
reliable moving hot air than most sleeve bearing fans and minimal
high-pitched whining compared to ball-bearing fans. The following fan is
louder than i'd want in a system yet if you're not able to replace the
heatisnk it may be necessary for moving enough air to compensate. Then
again I can only guess it will reduce the temp, I have some of these fans
but have never used one with an adapter on an AMD original heatsink.
http://www.svcompucycle.com/fba08a12h.html

If you know someone who's experienced in putting together Athlon systems
you might ask them to take a look at your heatsink and see if they can
swap in a different one. If it's difficult to get access to the clip it
might be necessary (or at least safest) to remove entire motherboard to
gain better access to the heatsink clip.
 
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