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Fortron PSU - 120mm fan = bad.

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Susquehannock

The Mad Smelter
Joined
Aug 26, 2003
Location
Maryland, USA
80mm BACK fan = (FSP300-60ATV)

120mm BOTTOM fan = (FSP300-60PN)


It seems like everyone is going hog wyld over the
Fortron 300-350w PSU with the large 120mm bottom fan.
However, after having two of the 300w Fortron models and
one 400w model, (two with 80mm back fan and one with the
120mm bottom fan) I would NOT recommend the
larger 120mm fan model.

Here's why:
While it may seem like a good idea to suck a little extra
air from the case, it's not generally a really good idea to expose
the guts of your PSU to the eXtra heat directly up from your HS&F.

Yes, the large 120mm fan might have better specs by itself.
However, once you get it situated in the bottom of the PSU the
airflow up through the components and out the back
is actually quite restrictive. And we all know how restricted air
can make a fan noisy.
The FSP300-60ATV with 80mm back fan appears
to have much more efficient airflow. Thus making less noise. :)

Not only that, the FSP300-60ATV netted in lower
CPU and case temps as well. The large fan was hogging air
from the back case fan. :(

Most importantly, all rails on both 300w PSU were
almost exactly the same under heavy load. (though the
FSP300-60ATV did have SLIGHTLY more stable rails)
 
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I figured that was or is a bad fan configuration.A 120mm fan with no where to go!A straight path of air is more efficent in cooling.
I figure on a large amount of blowback thru such a setup.The PSU
I have has 2 - 80mm fans inline,and a grill on the bottom of the PSU case to exit hot air should it build up.The best thing I did was cut both fan grids out of the PSU case.Now there is a good flow and the unit doesn't even get warm.I use the exhaust to cool my CRT.THE FANMAN:cool:
 
archilochus said:
I figured that was or is a bad fan configuration.A 120mm fan with no where to go!A straight path of air is more efficent in cooling.
I figure on a large amount of blowback thru such a setup.The PSU
I have has 2 - 80mm fans inline,and a grill on the bottom of the PSU case to exit hot air should it build up.The best thing I did was cut both fan grids out of the PSU case.Now there is a good flow and the unit doesn't even get warm.I use the exhaust to cool my CRT.THE FANMAN:cool:


Yeah, I wasn't too keen on the 120mm fan design either.
Just didn't seem to make sence.
There are a lot of people who really love the larger fan
on the bottom so I figured it was OK.
The fan is in a bad location IMhO. Nowehere else to put it
though.
On both of my cases I had to cut away the little metal PSU
shelf to accomodate the fan & grill. :rolleyes:
And what's worse is that I also had to really push and twist
on the PSU so one of the grill screws didn't hit that small horizontal
area just above the rear plug panel. :-/

Now that I've tried both I would definitely get
the 80mm fan model instead. No need for 2 or 3 fans
in this baby. Just the one fan seems to be all it really requires. :)
 
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squeakygeek said:


Isn't that what you'd be doing anyway?


Well, you're right in a way. It really depends on how
the fans are configured I guess.
As those of us who own AMD based boards know
many PSU have the bottom fan placed directly over the
CPU heatsink.
If your only exhaust is out a top fan or blow hole than I'd
say the air temps would be the same. But if you have an exhaust
fan right next to the CPU heatsink like I do the air drawn
into the back of the PSU might be a bit cooler than if it were
from directly over the CPU.
Here again, I am assuming the single PSU fan has only holes on
the front of the unit from which to draw air.
 
Susquehannock said:



Well, you're right in a way. It really depends on how
the fans are configured I guess.
As those of us who own AMD based boards know
many PSU have the bottom fan placed directly over the
CPU heatsink.
If your only exhaust is out a top fan or blow hole than I'd
say the air temps would be the same. But if you have an exhaust
fan right next to the CPU heatsink like I do the air drawn
into the back of the PSU might be a bit cooler than if it were
from directly over the CPU.
Here again, I am assuming the single PSU fan has only holes on
the front of the unit from which to draw air.

I think it would actually be advantageous to have the big psu fan right over the cpu, because the heat would escape the case much more quickly and efficiently. Your PSU may be a little warmer, but I don't think it would cause any problems. The extra fan is probably not there to help cool the PSU, but to provide better system exhaust.
 
No doubt about it, my system and CPU temps were a couple
degrees lower with the 80mm fan model. That may be because
of my fan configuration. Notwithstanding, I still say that more of
the air gets trapped inside the PSU with the fan on the bottom. Some have placed an 80mm on the back to compensate, but that
kind of defeats the purpose. For lower noise at least.

Again, I am talking about the two 300w units listed in my first
post. Things may be different with other models.

As always ... just my 2 cents. :thup:
 
i haven't dealt with any PSU's with the downward facing 120mm fans, but would it be possible to put them in the case upside down and cut a hole in the top of the case, so its sucking in air from outside the case or would putting it upside down affect the PSU functionality somehow?
 
well i actually like the 120mm fan model...i have a 120mm evercool aluminum fan exhausting air next to the cpu, and one fan in the front intake, the temps i have with my new case that all this stuff is in was never this good with my other crappy old antec case, besides...i like that 120mm fan :D
 
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