CPU fan

[norm]

I'm currently using the volcano 11 Xaser Edition on Athlon XP 2100+, Asus
A7N8X motherboard. I just recently moved everything into an Antec P160
aluminum case. I have two 120 mm fans, 1 front blowing in, and 1in back
blowing out. My CPU runs hotter now than the older steel case. I notice the
Volcano blows out not over the CPU.is this correct?



nc

 

[blackjack]

I am not sure of the Volcano blowing out, but you should try disconnecting
the fan blowing in so that you have just the exhaust. This is predicated
upon the fact that the air pressure inside the case is positive or close to
it and so the heat is not being transferred to outside the case. If the air
pressure inside of the case is negative then the heat will move and be
exhausted by the exhaust fan.

 

[Vic.]

I'm currently using the volcano 11 Xaser Edition on Athlon XP 2100+, Asus
A7N8X motherboard. I just recently moved everything into an Antec P160
aluminum case. I have two 120 mm fans, 1 front blowing in, and 1in back
blowing out. My CPU runs hotter now than the older steel case. I notice the
Volcano blows out not over the CPU.is this correct?

The p160 is touted as having good case airflow, and this may be the
root of your problem:

Both the big 120mm case fan and the cpu fan are trying to pull air
away from the heatsink. You could be experiencing some kind of
"stall", where the sum of these airflows is adding up to less than it
should and could.

I reckon that if you switch the cpu fan so that it's blowing onto the
heatsink, you'll see a worthwhile improvement in your temps. That way,
the cpu fan pushes air onto the cpu, and the rear case fan pulls the
hot air out of the box.

For the time it takes to remove and replace 4 screws, it's got to be
worth a try, and of course, I'm ready and waiting to be proved wrong!

Best,

Vic.

 

[David Besack]

I'm currently using the volcano 11 Xaser Edition on Athlon XP 2100+, Asus

A7N8X motherboard. I just recently moved everything into an Antec P160
aluminum case. I have two 120 mm fans, 1 front blowing in, and 1in back
blowing out. My CPU runs hotter now than the older steel case. I notice the
Volcano blows out not over the CPU.is this correct?

I can't imagine a situation where it would be desireable to _pull_ air from
the heatsink instead of blowing air onto it. The reason is because of the
force of the air going through the fan, it is forced into the fins of the
heatsink and then dispersed into the periphery. However, if you have the
fan pointing "up", it draws air mostly from the sides of the heatsink and
not from between the fins.

 

[norm]

Thanks for the suggestions and comments....
After reading your posts, there are a few things I didn't mentioned; The
case came with one back fan. Temps weren't satisfactory, so I added a second
fan to the front. This made little difference in the temps. Also, my power
supply is a dual fan...one fan above the cpu bowing into PS.
I like the suggestion of reversing the heatsink fan, I will attempt this
task this evening.

nc

 

[David Maynard]

I can't imagine a situation where it would be desireable to _pull_ air from
the heatsink instead of blowing air onto it. The reason is because of the
force of the air going through the fan, it is forced into the fins of the
heatsink and then dispersed into the periphery. However, if you have the
fan pointing "up", it draws air mostly from the sides of the heatsink and
not from between the fins.

Actually, it's the other way around. Fans 'blow' the air radially, not
'down', and there's no airflow at all in the center, unless it is deflected
there somehow. Unfortunately, the center, where there is the least 'blow',
is where the majority of the heat is.

You are correct that the suction side of the fan will pull air from the
'sides' (and also the center and everywhere else), if it can get it from
the sides. But to make sure that doesn't happen, heatsinks designed for
'blowing upwards' are usually fitted with a top shroud that forces the air
intake at the bottom of the heatsink. And, since air will follow the path
of least resistance, it has a tendency to equalize across the entire
heatsink volume, which tends to cause more airflow in the center of the
heatsink than a 'blow down' arrangement.

 

[norm]

Actually, it's the other way around. Fans 'blow' the air radially, not
'down', and there's no airflow at all in the center, unless it is deflected
there somehow. Unfortunately, the center, where there is the least 'blow',
is where the majority of the heat is.

You are correct that the suction side of the fan will pull air from the
'sides' (and also the center and everywhere else), if it can get it from
the sides. But to make sure that doesn't happen, heatsinks designed for
'blowing upwards' are usually fitted with a top shroud that forces the air
intake at the bottom of the heatsink. And, since air will follow the path
of least resistance, it has a tendency to equalize across the entire
heatsink volume, which tends to cause more airflow in the center of the
heatsink than a 'blow down' arrangement.

I looked at Thermaltake web site and didn't find any infomation on correct
fan direction. I don't remember ever changing it though. However, I had
heat problem there too.

 

[norm]

I looked at Thermaltake web site and didn't find any infomation on correct
fan direction. I don't remember ever changing it though. However, I had
heat problem there too.

Oops referring to my older case

 

[David Maynard]

I looked at Thermaltake web site and didn't find any infomation on correct
fan direction. I don't remember ever changing it though. However, I had
heat problem there too.

Well, I wasn't talking about any particular heatsink. I was just replying
to Besak's comment that he couldn't imagine a situation where exhausting
outwards would be useful.

Alpha almost always recommends exhausting outwards with their heatsinks but
most manufacturers make them as 'blow down'. But a casual look at the
volcano isn't enough for me to really tell.

Although visiting their web site was an interesting experience as they've
come out with a 'fanless' heatpipe heatsink. I was wondering when someone
would finally get around to making one like that.

http://www.thermaltake.com/coolers/cl-p0019Fanless103/cl-p0019fanless103.htm