[Going further OT] Re: Leaving a server on all day
Hi,
What is so bad with the floor?
Ever move into a beautiful house only to find the floor *flooded* at the
first serious cloud break? ;-)
BTW - I'd make sure I'd get/have a decent computer case with a decent
PSU with enough room for some decent 80mm or larger low noise fans
rather than opening up the side panel. Perhaps an aluminum (Chieftec
Dragon, anyone?) case with some Enermax and Zalman coolers and PSU might
do the trick. I've {b,s}een told a good airflow (front to back) is king.
OT nonetheless and good luck... Nico
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Re: [Going further OT] Re: Leaving a server on all day
Nico Meijer [EMAIL PROTECTED] wrote:
Hi,
What is so bad with the floor?
Ever move into a beautiful house only to find the floor *flooded* at the
first serious cloud break? ;-)
BTW - I'd make sure I'd get/have a decent computer case with a decent
PSU with enough room for some decent 80mm or larger low noise fans
rather than opening up the side panel. Perhaps an aluminum (Chieftec
Dragon, anyone?) case with some Enermax and Zalman coolers and PSU might
do the trick. I've {b,s}een told a good airflow (front to back) is king.
I saw an article recently by a guy who had a degree in thermal dynamics or
something that was dispelling the common myths about PC cooling.
His conclusion was basically that airflow is king. You need to move air across
the heat sinks that is cooler than the heat sinks are. Sounds simple, but the
overall conclusion was that you could improve cooling without increasing noise
by ensuring that air from _outside_ the case was flowing directly over the
processor heatsink. Reason this works well is becuase the air inside the case
is usually considerably warmer than the air outside the case, and moving warm
air across the heat sink doesn't accomplish much. By drawing cool air in from
outside the case, things stay cooler.
Anyway, his suggestion was that the best thing you could do for your cooling
rig was to purchase/fab one of those little duct kits that allows the cpu fan
to pull air from outside the case. Some cases even have the duct built in (my
brother's computer does).
--
Bill Moran
Potential Technologies
http://www.potentialtech.com
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Re: [Going further OT] Re: Leaving a server on all day
Bill Moran wrote:
Nico Meijer [EMAIL PROTECTED] wrote:
Hi,
What is so bad with the floor?
Ever move into a beautiful house only to find the floor *flooded* at the
first serious cloud break? ;-)
BTW - I'd make sure I'd get/have a decent computer case with a decent
PSU with enough room for some decent 80mm or larger low noise fans
rather than opening up the side panel. Perhaps an aluminum (Chieftec
Dragon, anyone?) case with some Enermax and Zalman coolers and PSU might
do the trick. I've {b,s}een told a good airflow (front to back) is king.
I saw an article recently by a guy who had a degree in thermal dynamics or
something that was dispelling the common myths about PC cooling.
His conclusion was basically that airflow is king. You need to move air across
the heat sinks that is cooler than the heat sinks are. Sounds simple, but the
overall conclusion was that you could improve cooling without increasing noise
by ensuring that air from _outside_ the case was flowing directly over the
processor heatsink. Reason this works well is becuase the air inside the case
is usually considerably warmer than the air outside the case, and moving warm
air across the heat sink doesn't accomplish much. By drawing cool air in from
outside the case, things stay cooler.
Anyway, his suggestion was that the best thing you could do for your cooling
rig was to purchase/fab one of those little duct kits that allows the cpu fan
to pull air from outside the case. Some cases even have the duct built in (my
brother's computer does).
Ok, I'll chime in here. Here's what everything I ever learned about
heat transfer and fluid flow tells me:
Everything Bill is saying is correct. The best way to cool is to move
as much fluid (air is a fluid for the purpose of this discussion) as
fast as possible across whatever is hot. Of course, the fluid has to be
cooler than whatever is being cooled. A fan rotating at certain speed
is going to push a given volume of air in a given amount of time. By
leaving the case covers on and providing only a few small holes for
the air to travel through, you're going to force the air coming through
those holes to travel through the case faster.
That being said, if the case design, component placement, etc. is such
that leaving the the cover off actually allows a significantly greater
volume of air to get to the heatsink(s) in a given amount of time, then
leaving the cover off is a good thing.
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Re: [Going further OT] Re: Leaving a server on all day
On Tuesday 08 June 2004 01:45 pm, Jason Taylor wrote: Bill Moran wrote: Nico Meijer [EMAIL PROTECTED] wrote: Hi, sniping a lot off Everything Bill is saying is correct. The best way to cool is to move as much fluid (air is a fluid for the purpose of this discussion) as fast as possible across whatever is hot. Of course, the fluid has to be cooler than whatever is being cooled. A fan rotating at certain speed is going to push a given volume of air in a given amount of time. By leaving the case covers on and providing only a few small holes for the air to travel through, you're going to force the air coming through those holes to travel through the case faster. That being said, if the case design, component placement, etc. is such that leaving the the cover off actually allows a significantly greater volume of air to get to the heatsink(s) in a given amount of time, then leaving the cover off is a good thing. I have 2 identical machines (AMD 2400+'s) except that one has 2x120mm fans (push pull) and the other doesn't. The one that has 1x120mm fan has Sonata punched in the covers at the top of the front and back covers and that case runs 3-5oC cooler than the other case. I leave the cover off of the other one to keep things running cool. They both run setiathome 24x7 and generate equal amounts of heat. I don't like cpus running close to 50oC or higher. Kent -- Kent Stewart Richland, WA http://users.owt.com/kstewart/index.html ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: [Going further OT] Re: Leaving a server on all day
On Tue, 8 Jun 2004, Jason Taylor wrote: Ok, I'll chime in here. Here's what everything I ever learned about heat transfer and fluid flow tells me: Everything Bill is saying is correct. The best way to cool is to move as much fluid (air is a fluid for the purpose of this discussion) as fast as possible across whatever is hot. As a point of interest, as fast as possible isn't always correct, though it may be WRT practical case-cooling considerations. One consideration in designing race cars, especially those using stock engines, is to not overdrive the water pump at high rpms. Not because of cavitation, because you can flow water through the engine faster than is optimal for heat dissipation. Non intuitive, but true - has to do with the heat transfer across the water/metal surfaces and is otherwise over my head. ;) KeS ___ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
OT: The fan club (was: Re: [Going further OT] Re: Leaving a server on all day)
On 8 Jun 2004 at 13:45, Jason Taylor wrote:
Bill Moran wrote:
Nico Meijer [EMAIL PROTECTED] wrote:
BTW - I'd make sure I'd get/have a decent computer case with a decent
PSU with enough room for some decent 80mm or larger low noise fans
rather than opening up the side panel. Perhaps an aluminum (Chieftec
Dragon, anyone?) case with some Enermax and Zalman coolers and PSU might
do the trick. I've {b,s}een told a good airflow (front to back) is king.
I saw an article recently by a guy who had a degree in thermal dynamics or
something that was dispelling the common myths about PC cooling.
His conclusion was basically that airflow is king. You need to move air across
the heat sinks that is cooler than the heat sinks are. Sounds simple, but the
overall conclusion was that you could improve cooling without increasing noise
by ensuring that air from _outside_ the case was flowing directly over the
processor heatsink. Reason this works well is becuase the air inside the case
is usually considerably warmer than the air outside the case, and moving warm
air across the heat sink doesn't accomplish much. By drawing cool air in from
outside the case, things stay cooler.
Anyway, his suggestion was that the best thing you could do for your cooling
rig was to purchase/fab one of those little duct kits that allows the cpu fan
to pull air from outside the case. Some cases even have the duct built in (my
brother's computer does).
Ok, I'll chime in here. Here's what everything I ever learned about
heat transfer and fluid flow tells me:
Everything Bill is saying is correct. The best way to cool is to move
as much fluid (air is a fluid for the purpose of this discussion) as
fast as possible across whatever is hot. Of course, the fluid has to be
cooler than whatever is being cooled. A fan rotating at certain speed
is going to push a given volume of air in a given amount of time. By
leaving the case covers on and providing only a few small holes for
the air to travel through, you're going to force the air coming through
those holes to travel through the case faster.
That being said, if the case design, component placement, etc. is such
that leaving the the cover off actually allows a significantly greater
volume of air to get to the heatsink(s) in a given amount of time, then
leaving the cover off is a good thing.
Okay, no degree in thermal here, but I used to design these things for
a living (Dell, Tandem, Datapoint). Sorry I missed the start of this
thread, but I'll jump in here and see how much confusion I can
generate.
The generalities above are generally true, generally. :-)
Leaving a cover off may help or it may hurt, depending upon what's hot
in the case and how leaving the cover off affects airflow over those
items. What you're interested in is a maximum of airflow (volume more
than velocity) and a maximum of temperature delta specifically at the
hot components. (This assumes the temp of the air is lower than the
hot component. If it's warmer than the hot component your house is
probably on fire and you've got bigger problems.)
You're also interested in things like maximum surface area at the
heatsink/fluid interface, but that's a function of heatsink design, not
fan design or placement, and there are other factors influencing the
design of that interface. Obviously, if heatsink blades are crosswise
to the airflow the heatsink will be much less efficient.
If the case is really well designed, the incoming air is directed at
the hot components. Since cases are generally generic and motherboards
don't always put things in the same place, this may or may not be
achieved. This matchup issue is one of the reasons generic cases
usually don't have ducts, since a misdirected duct is worse than no
duct. If you're Dell or HP and control both the MB and the case, you
can use good, cheap ducts to allow the use of cheaper heatsinks because
you know where everything is. If the incoming cool air is not directed
at the hot components, leaving off the cover may actually help, but if
the case and motherboard are a good match leaving off the cover can
disrupt the planned flow.
For moving a lot of air with low noise, go for the largest fan you can
and run it slow. The cases I'm using these days to build workstations
are Antec Sonatas, and I mount two 120 mm fans, one in front and one in
the rear, one exhausting and one intaking (therefore in series). I
wish they had proper ducting like the Fong Kai 603 I used to use, but
our components are staying cool enough and the noise level is low. If
you prefer aluminum, the Antec Super LANboy is very similar to the
Sonata, and we have one of these for a machine we carry around quite a
bit. Aluminum is a great help for weight, but I doubt it adds much to
cooling unless you're mounting heatsinks directly to your case. Most
of the heat will leave with the
