View Single Post
  #3  
Old June 21st 12, 05:37 PM posted to alt.comp.hardware.overclocking.amd
Seasidepeter
external usenet poster
 
Posts: 10
Default Swapping a cooler fan

On 21/06/2012 15:20, Paul wrote:
Seasidepeter wrote:
Hi all - I recently upgraded my asus m2n68 motherboard with a Phenom 2 x4 955
cpu - a decent step up from the original Athlon 64x2 2.7Ghz.

Everything runs great - but the supplied cooler for the Phenom has a really
noisy fan.

Any reason I can't swap just the fan, leaving the heatsink in place? They look
about the same size...?


That depends on the CFM rating of each fan.

In general terms, if you look at catalog listings for computer fans,
they come in "low", "medium", "high", and "ultra". "Low" and "medium"
are the ones you can live with. The noise from an "ultra", will send
you into the next room. If you had a "high" or "ultra", you'd use a
voltage reducer with them (like a Zalman Fanmate), to crank down
the speed, and the noise. On my other computer, I have a 110CFM
fan, which I run at 7V, so the noise isn't quite as bad. That's
the rear exhaust fan.

If you drop the fan by one "size", then the CPU temp is going to
increase by a bit, say 10C. You have to use a tool like Speedfan,
see what the current temp is. Then, read up on what other AMD
processor users consider a stable operating temperature to be.

For example, my CPU runs at 43C, when room temp is quite cool. Maybe
my processor can run up to 65C socket temp, without a problem. I have
22C of headroom to work with. In my computer room, a hot summer day
(i.e. yesterday!), the temp shoots up by an additional 12C.
So my estimate for how hot the computer gets (before I shut down
and exit the room), would be 43C+12C = 55C at the CPU. I have
about 10C left of headroom, which might be just enough to downsize
one fan grade.

The above fan grades, are for the same size fan. In the catalog,
I might see four 120mm fans, with those four designations. If my
CPU was cooled by a "high", then I might be able to move down to
a "medium" and stay within my desired 65C limit.

When you do that kind of testing (CPU max temp), you need to run
a CPU loading program. That would simulate a real usage scenario.
For example, if I do a two hour video render, with all four cores,
then walk out of the room, I want to be sure if I come back in
two hours, the CPU stays under 65C. To simulate that, I can run
Prime95 torture test, wait ten minutes, and that test case will
give me an estimate of how hot the CPU would get. (The ten minutes,
is to give the computer case internal air temperature time to settle
down. It takes a while, and even ten minutes might not be enough.)
You want to work with "worst case" conditions, so you don't underestimate
your headroom remaining. If you're doing the experiment on a
winter day, you need to know the summer to winter room temp
differential, and add that in to the experimental results. If
you're doing the experiment on the hottest day in the summer,
then no further correction is needed.

Speedfan from almico.com, can be used to read out your
temperature sensors. Other available tools would be
Asus Probe, one of the MSI or Gigabyte utilities, CoreTemp,
MBM5 or the like. Whatever utility that knows the hardware
monitor best.

I have no idea what a Phenom II x4 can take in terms of temperatures,
but they do use a few watts, and need a decent cooling solution.
My processor is only a dual core, and flat out, uses about 36 watts of
electricity (as measured). So I don't need that much of a fan. I
actually replaced the fan on my cooler, but it was because I
broke the original one (doh!). You can't be too rough with them,
when cleaning the dust off. Some spring inside mine, slipped out
of place, and it was ruined. Mine was a Coolermaster brand.
Replaced it with a Vantec Stealth.

I don't clean the computer that often, but was thinking about
it just now, because yesterday was so hot. And today is
going to be another stinker.

So your first step, is researching the "max stable temp" for
a Phenom II x4.

Paul

Thank you Paul - a really helpful response. I've downloaded the programs you
suggested, and gone ahead and swapped the two fans. The old one is exactly the
same size, but the blades are thinner, which probably limits to amount of air it
can pull.

With no overclocking, the cpu seems to idle at around 42/43C. Under the torture
test it rises to 62, at which point I stopped the test. Call me a chicken, but I
don't want to blow it up just yet!

Under ordinary conditions - word processing, web browsing, emailing, running
Black Ops in a window (purely for research, you understand!), it seems to run at
a steady-ish 55C.

The plus side is the wonderful silence; the negative side is that I suspect it
needs a bigger fan...time to check those catalogues I guess.