Recommendations on cool hard drive

[Rod Speed]

J.Clarke wrote

I'm sorry about seeming to have that impression.
Maybe I haven't been verbose enough.

Or you keep waffling on about complete irrelevancys.

All that really matters in getting cool air in and warmed
air out of a case (admittedly only part of cooling) is a
pressure differential between the entrance and exit.

More silly waffle. It aint necessarily about a pressure differential,
most obviously with what Intel calls series and parallel fans.

The most efficient way to do that is:
1) let gravity aid it by putting the
entrance low and the exit high,

Thats utterly mangled too. What you're actually doing
by having the fan that moves air out of the case high is
recognising the fact that hot air will rise in the case.

And having the fan that moves air into the case low
ensures that the air does flow thru the bulk of the
case. If that fan was high too, you may well not
see that much airflow in the bottom of the case at all.

2) keep the path straight as possible,

More mindlessly silly stuff. In fact with just the power
supply fan and a single fan at the bottom moving air
into the case, the path is nothing like straight and it
would be completely stupid to have that extra fan where
the path is straight, because you would then have no
fan assisted airflow in much of the bottom of the case.

3) keep the path clear of obstructions as possible (e.g.
by use of short "round" cables, use of cable ties, etc).

More mindlessly silly stuff. The airflow will move around
ribbon cables fine with a decent fan assisted airflow.

And its completely stupid to be flouting the
cable standards by using stupid round cables.
If the airflow isnt adequate with normal cables,
you're much better off moving more air with
better fans than using stupid round cable kludges.

And it makes more sense to minimise the number
of hard drives in the case than it does to do either.

Beyond that, it doesn't matter if air is blown in or
blown out or a comination of blowing in/blowing
out is used - as long as the pressure at the
entrance is higher than the pressure at the exit.

Utterly mangled all over again.

What matters is the VOLUME OF AIR MOVING
THRU THE CASE and that has **** all to do
with that waffle of yours about pressure.

But if you introduce passive holes in the case,

Wots an active hole in the case ?

that differential is hard to design and maintain.
Bullshit.

Harder, yet, is the path of air flow when you have such holes.

More bullshit.

Most ATX cases are designed with an active
(fanned) exit and a passive (multiple holed)
entrance with the straightest path available
- diagonally from bottom/front to top/rear.

So much for your silly waffle about a straight path.

When you add blowing into the case at some
intermediate point, the pressure differential is
reduced between that point and the entrance holes,

Completely off with the fairys, as usual.

And anyone with any sense puts a fan like that at
the bottom of the case at the front, because thats
what produces the best airflow thru the bulk of the
case where most of the heat sources are.

and flow at the entrance is thereby reduced.

Mindlessly silly. The total amount of air entering
the case INCREASES because you've got a
****ing fan pumping it into the case, stupid.

But there are reasons to use interior fans that don't
have an effect on this pressure differential - to help
direct the interior air flow and to increase turbulence
against components. Good examples of this are fans
that blow air against CPU and graphic cards' heatsinks.

Must be one of those rocket scientist children.

Pity it doesnt have a damned thing to do with any
'pressure differential' you keep waffling on about.

Another example is a fan that blows air directly against
the face of a hard drive. It doesn't bring in any fresh air,
but it does direct the flow against the hard drive's largest
metal surface and it increases the turbulence of that flow.

Its just about increasing the airflow over the drive, stupid.

Such would also be the effect of a non-gasketed fan

God knows what this silly shit about gaskets is about.

just inside the lower front entrance of the case - it would
maintain air velocity and turbulence against the primary
hard drive (if their positions were right) - and lowered
temperatures measured at the hard drive via SMART
would lead the naive to think that an increased intake
flow had been accomplished when, in fact, it hadn't.

Hasnt got a damned thing to do with using the SMART
temperature of the drive to see that your stupid claims
about DRIVE BAY COOLING IN THE 5.25" BAY STACK
HAS ANY EFFECT ON THE TEMPERATURE OF THE
DRIVES IN THE MAIN 3.5" BAY STACK, STUPID.

 

[Rod Speed]

Cooling a PC case can get rather involved. I have a 1999 Intel paper on
cooling ("ATX Thermal Design Suggestions version 1.0," atx_thermal_dg1.pdf).
You should be able to find a newer version on their site. If not, I can
email the old copy I have to anyone who wants it. It's 449kB. I also have
a 1999 paper named "ATX Thermal Design Guide" (PADSTDS_10.pdf, 1.7 MB).

An interesting excerpt:

"Multiple fans can be used in two combinations, parallel and series.

* Two fans in parallel, Q = Q1 + Q2 at zero back pressure
(Q = volumetric flow)
* Two fans in series, p = p1 + p2 at zero airflow
(p = static pressure)

An example of a parallel fan combination is a system fan and a power supply
fan both either pressurizing or evacuating a chassis. Ideally, a parallel
fan combination doubles the system airflow. An example of a series fan
combination is a system fan blowing air into the chassis and a power supply
fan exhausting air from the chassis. Ideally, a series fan combination
doubles the system's ability to overcome built-up back pressure. In
reality, because of venting, leakage, and design compromises, when we employ
multiple fans, we often are implementing a combination series/parallel
configuration. The effect of employing series/parallel fan combinations is
shown in Figures 2.4 and 2.5.

Employing multiple (identical) fans in a system does provide some marginal
increase in airflow. The exact amount depends on many factors, including
fan speed and configuration, as well as chassis airflow impedance. If the
fans are not identical, then the figures will change slightly, but the
treads will be similar. The general rule is, if the chassis has high
impedance, place the fans in series. If the chassis has low impedance,
place the fans in parallel."


So if your system has medium or average
air flow impedance (how would you know?),

Its obvious from how congested it is inside the case,
mostly by ribbon cables, and how air can enter the
case with just fans that move air out of the case.

should fans be in series or in parallel?

Generally its better to have them in series if you are
adding just one fan to the original power supply fan.
So you dont get the effect you are getting with airflow
thru the power supply dropping substantially.

Does a second fan even do any good if not blowing directly onto
something that needs special attention (the above excerpt says
extra fans provides only a "marginal" increase in airflow)?

Its just plain wrong there.

Maybe it's better to have a more powerful single fan.

Nope. And thats why you dont see that config used much.

Considering the location of the fans in my PC case I think the answer
is clear, they should be in parallel (both blowing out the rear).

Nope, because you get that problem with reduced airflow thru
the power supply you are getting when the two fans arent
the same size and dont have the same restrictions of airlow.

But if I had a 5.25" drive bay cooler for my HD, should it blow in or out?
In.

My guess is out.
Nope.

A fan in the lower front is probably worth little to nothing unless
your HDs are mounted there and the fan is blowing in directly on them.

Thats just plain wrong. Even when the drives get adequate
airflow over them without that fan, adding that fan does
move more air thru the case and if you have a substantial
source of heat with an Athlon cpu, you'll find that the cpu
temp does improve substantially with that fan added. Just
because more air moves thru the case, and that air does
move past the cpu with its own heatsink and fan and so
the hot air from that biggest source of hot air gets move
out of the case better than without the front fan assisting
the power supply fan moving air thru the case.

Two 80 mm fans or one 100 mm fan in the lower front
of these cases provide air for 3-5 HDs mounted right
in front of the fans. No question about good HD cooling.

Yes, but the other alternative is not have 5 HDs too.

And if you do need a substantial number of HDs
for say RAID5, you're better off with a case thats
designed from scratch for a decent number of drives.

 

[J.Clarke]

I'm sorry about seeming to have that impression.
Maybe I haven't been verbose enough.

All that really matters in getting cool air in and warmed
air out of a case (admittedly only part of cooling) is a
pressure differential between the entrance and exit.
The most efficient way to do that is:
1) let gravity aid it by putting the entrance low and the
exit high,
2) keep the path straight as possible,
3) keep the path clear of obstructions as possible (e.g.
by use of short "round" cables, use of cable ties, etc).

Beyond that, it doesn't matter if air is blown in or blown
out or a comination of blowing in/blowing out is used -
as long as the pressure at the entrance is higher than the
pressure at the exit. But if you introduce passive holes
in the case, that differential is hard to design and maintain.
Harder, yet, is the path of air flow when you have such
holes.

Most ATX cases are designed with an active (fanned)
exit and a passive (multiple holed) entrance with the
straightest path available - diagonally from bottom/front
to top/rear. When you add blowing into the case at
some intermediate point, the pressure differential is
reduced between that point and the entrance holes,
and flow at the entrance is thereby reduced.

But there are reasons to use interior fans that don't have
an effect on this pressure differential - to help direct
the interior air flow and to increase turbulence against
components. Good examples of this are fans that blow
air against CPU and graphic cards' heatsinks. Another
example is a fan that blows air directly against the face
of a hard drive. It doesn't bring in any fresh air, but it
does direct the flow against the hard drive's largest metal
surface and it increases the turbulence of that flow. Such
would also be the effect of a non-gasketed fan just inside
the lower front entrance of the case - it would maintain
air velocity and turbulence against the primary hard drive
(if their positions were right) - and lowered temperatures
measured at the hard drive via SMART would lead the
naive to think that an increased intake flow had been
accomplished when, in fact, it hadn't.

Now, have you actually performed the CFD on any of this for a typical
computer case or done a smoke test or poked an anemometer into one, or
are you just stating an opinion?

 

[John H.]

If your power supply is a typical "low noise" design then the fan is
thermally controlled--if the second fan is handling most of the cooling
load for the case then the power supply will never get hot enough to
move its fan off of the lowest speed.

My PS is a 'let's do it the cheap way' "low noise" design. They simply used
one of the lowest powered 80mm fans available (.9W) and lowered the PS's
power rating from 300w to 275w. There is no thermal control, RPM
monitoring, dancing neon lights or any of that "fancy" stuff. I've learned
my lesson though, next time I'm getting a power supply with 2 or 3 fans and
every feature (except maybe for the lights ).

 

[John H.]

Its obvious from how congested it is inside the case,
mostly by ribbon cables, and how air can enter the
case with just fans that move air out of the case.

It's not always obvious which way and where extra fans should go even when
you know the general rules. Or you might think you know and be wrong. Trial
and error works best sometimes.

Generally its better to have them in series if you are
adding just one fan to the original power supply fan.

I'd call my case low impedance which should mean that parallel is better for
me. If I had a very hot running CPU, then a front fan blowing in with
perhaps an air guide directing some or all of the air toward the CPU would
help greatly. Or a front fan blowing in on HDs helps. But if there are no
"hot spots" in your case such as those, then a series front fan is doing
what?

So you dont get the effect you are getting with airflow
thru the power supply dropping substantially.

I believe my problem is low power fans. BTW, I checked the labels on the
fans and they're both the same size and power, 0.9W, which is about as low
as they come for the 80mm size. If both fans were, say, 2W fans, there
would still be a difference (lower air flow for the PS) but so what if the
PS air flow is high enough.

Its just plain wrong there.


Nope. And thats why you dont see that config used much.

I liked the old Apple Cube with one low RPM, low noise, 8" fan.

You don't see more powerful 80mm fans used in PCs because of the noise
(although there is a 9.1W 80mm fan (Vantec Tornado) for those who don't care
about noise). Considering all the noise made by other fans (CPU, video
board), perhaps some people (including me) have worried too much about case
and PS fan noise. I do wish 120mm fans were used more (more air yet lower
RPM and noise). No reason why a top, side or front fan can't be 120mm. I
like the idea of a top fan - that's where the heat goes.

Nope, because you get that problem with reduced airflow thru
the power supply you are getting when the two fans arent
the same size and dont have the same restrictions of airlow.

As I explained above, my fans are the same size after all, but of course the
PS has a more restricted airflow. Anytime you have 2 fans in parallel both
fans have reduced air flow unless the chassis impedance is zero. Since it's
not, you never get 2x the air flow (with equal fans). Solution: size each
fan to compensate (or use more powerful fans and forgetaboutit).

Having a 2nd rear fan blowing in instead of out would increase the air flow
through the PS alright but it would also reduce the total air flow through
the case. Why not instead just make the PS fan bigger if need be? With new
power supplies having 2 or even 3 fans now, having an extra rear fan blowing
out (if you still need one!) should be no problem at all.

Nope.

I agree. I want cooler outside air blowing in on the HD, not hot inside
air moving the other way (as I discover below).

Thats just plain wrong. Even when the drives get adequate
airflow over them without that fan, adding that fan does
move more air thru the case and if you have a substantial
source of heat with an Athlon cpu, you'll find that the cpu
temp does improve substantially with that fan added. Just
because more air moves thru the case, and that air does
move past the cpu with its own heatsink and fan and so
the hot air from that biggest source of hot air gets move
out of the case better than without the front fan assisting
the power supply fan moving air thru the case.

I was going by what Intel said, that fans in series won't make much
difference in air flow unless your case has high impedance (which makes
sense to me). What you say above makes sense too, though I think it's not
"more air" as much as redirected air that gives the benefit.

I decided to try it anyway by moving the rear fan to the front (blowing in
instead of out).

As expected it does increase the air flow through the PS (even simply
removing the side cover did that). But it's cooking my HDs. Instead of
running at 36C (HD mounted in 3.5" slot) and 39C (5.25" slot), they're now
running at 38C and 44-45C (with no HD activity - I don't think I'd want to
run a seek test now). The front fan blows in but where does this air come
from? The bezel on my case allows the air to come from its bottom edge or
from any opening on the front of the frame, including the wide open 5.25"
slot used for the HD (once the cover is broken off to allow installing the
HD it can't be put back). So now, instead of the HD getting at least *some*
cool air from the outside, it's apparently being "cooled" with hot air from
the inside. The fan will be going back to the rear.

So if I replace the fans, which is better, the Vantec TF8025 temperature
controlled (1.8-2.8W) fan with an RPM monitoring cable, or the Panasonic
Panaflo with no RPM monitoring? I'm thinking the Vantec is better.

Yes, but the other alternative is not have 5 HDs too.

And if you do need a substantial number of HDs
for say RAID5, you're better off with a case thats
designed from scratch for a decent number of drives.

I gave the range that I've seen, 3-5. 3 hidden slots (with a fan in front
of them) would suit me fine (saving maybe a dollar or two over having 5). I
always have 2 drives and it's nice to have room for one extra, even if it's
only used temporarily when upgrading a drive. And even with 1 HD it's nice
to have good cooling.

 

[J.Clarke]

...or spent 20 years around Experimental Aircraft Assoc.
activities; or read numerous publications on airflow
over/around/through airframes, instrumentation and engine
comparments; or helped a couple guys build homebuilt
aircraft; or have earned a pilot's license; or have worked
in the aerospace industry; or have a degree in physics;
or have futzed with my own PC? I dunno. Which do you
consider most important? What I contribute is some
understanding of basic sub-sonic fluid flow and thermal
management based on formal and informal study, without
any hardware sellers' "folklore" or Usenet trolling.

In other words you're stating an opinion.

I don't consider any of your claimed qualifications to be important. I
consider the results of calculations or tests to be important. Until
you have produced same you're just another guy expressing an opinion.

Incidentally, everything you list I've done. Plus grad school in
aeronautical engineering.

 

[J.Clarke]

"If More is Better, then Too Much is Just Right."
- old hot rodder saying regarding horsepower

I would apply the hot rodder principle in regards to PC
case cooling (providing you can stand the whoooshing
sound). I mean, you can only cool anything to the
temperature of the room, at best. Can room temperature
be too low for PC components?

You can cool to well below room temperature. Commercially available PC
cooling products (Koolance, Vapochill, Prometeia and others) will cool a
CPU to-20C or more, and some experimenters have been cooling their PCs
with liquid nitrogen.

 

[Timothy Daniels]

I decided to try it anyway by moving the rear fan to the front (blowing in
instead of out).

As expected it does increase the air flow through the PS (even simply
removing the side cover did that). But it's cooking my HDs. Instead of
running at 36C (HD mounted in 3.5" slot) and 39C (5.25" slot), they're
now running at 38C and 44-45C (with no HD activity - I don't think I'd
want to run a seek test now). The front fan blows in but where does this
air come from? The bezel on my case allows the air to come from its
bottom edge or from any opening on the front of the frame, including the
wide open 5.25" slot used for the HD (once the cover is broken off to
allow installing the HD it can't be put back). So now, instead of the HD
getting at least *some* cool air from the outside, it's apparently being
"cooled" with hot air from the inside. The fan will be going back to the
rear.

That's the usual trouble with front fans and bezeled cases - there
are so many holes in the front that even if you seal the fan shroud right
up against the case, air can bypass the fan in either direction. The only
advantage to having a fan anywhere near the front of such cases (either
inside or outside the case wall) is to add turbulence to the air impinging
on the hard drive(s).

Following the principle of directing interior air directly against the
face of hard drives without attempting to use fresh outside air are
several cooling fans that can be referred to as "low profile" hard drive
fans. Here are just a few examples:
http://www.tigerdirect.com/applications/category/category_slc.asp?CatId=495
These fans just pressurize the air directly over the face of the hard drive
and allow the air to squirt out sideways, parallel to the surface of the
face.
Assuming that the interior air of the case in the vicinity of the fans is
lower
than that of the hard drive, this will increase the cooling effect over that
obtained by simple laminar flow. I can't find the review now, but I recall
reading a review awhile back that found a worthwhile temperature drop
by use of such a "low profile" fan. The advantage, of course, is not
upsetting
the overall flow pattern within the case by not changing the interior
pressure.


*TimDaniels*

 

[Rod Speed]

It's not always obvious which way and where extra
fans should go even when you know the general rules.

Sure, but thats a completely different question to the one at the top.

Or you might think you know and be wrong.
Trial and error works best sometimes.

Yes, which is why I kept rubbing Timmy's nose in
the trivial proof on that question of whether a drive
bay cooling in a 5.25" bay is going to have any effect
on the airflow over drives in the main 3.5" drive bay
stack, by actually measuring their SMART temperature
with the 5.25" bay cooling turned on and turned off.

I'd call my case low impedance which
should mean that parallel is better for me.

Its more complicated than that, particularly
when you have the two fans close to each other
and moving completely different amounts of air.

While the fan on the back of the case blowing out
will certainly move more air out of the case than the
PSU fan does, you can get a situation where you are no
longer moving enough air thru the PSU to cool it properly.

But if the PSU fan speed is varied with the temperature
of the air inside the PSU, it may just be not moving much
air because the temperature inside the PSU is fine with
the other fan moving most of the warm air out of the case.

If I had a very hot running CPU, then a front fan
blowing in with perhaps an air guide directing some
or all of the air toward the CPU would help greatly.

You dont really need to direct it to the cpu
when the cpu has its own heatsink and fan.

And if you are going to have the fan moving air into
the case, its generally best to do that at the bottom
front of the case, so that air moves thru the bulk of
the case and ends up going out thru the PSU.

Or a front fan blowing in on HDs helps. But if
there are no "hot spots" in your case such as those,

There always are significant hotspots in modern system,
if only the cpu and next the video card if its a gaming card.

then a series front fan is doing what?

Assisting in the movement of air thru the bulk of the case.

Sure, a fan on the back of the case blowing out will also
see significant movement of air thru the bulk of the case,
with the air coming in the holes that are usually at the
bottom and front of the case. But you can end up with
reduced airflow thru the PSU if you dont watch out.

I believe my problem is low power fans.

Yes, and it could just be that with the fan on the back of the
case moving the bulk of the warm air out of the case, thats
not going thru the PSU anymore, and if the PSU fan is temp
controlled, so its as quiet as possible, it may just be running
slower than without the extra fan, because the PSU is cool enough.

BTW, I checked the labels on the fans and they're
both the same size and power, 0.9W, which is
about as low as they come for the 80mm size.

Sure, but the PSU fan see much more air resistance, thru the PSU.

And may be temperature controlled too.

If both fans were, say, 2W fans, there would
still be a difference (lower air flow for the PS)

Yes, because the resistance is much higher thru the PSU.

but so what if the PS air flow is high enough.

Yep. But if it isnt temp controlled, its a bit of a worry
that currently not much air appears to be moving thru it.

The obvious test is the temperature inside the
PSU but thats not quite so easy to measure safely.

It'd be easier to check if it is temperature controlled.

I liked the old Apple Cube with one low RPM, low noise, 8" fan.

Sure, but thats a different situation to modern PCs, particularly
Athlons, with a significant amount of heat produced by the cpu.

You don't see more powerful 80mm
fans used in PCs because of the noise

No reason why a low noise fan cant be used.

Its more a consequence of the form factor of the PC
PSU. There just aint the room for a single 8" fan in there.

(although there is a 9.1W 80mm fan (Vantec Tornado)
for those who don't care about noise). Considering all
the noise made by other fans (CPU, video board),

There doesnt have to be. Most of the Intel cpus
have very quiet boxed fans. The last one I installed
I had to look very carefully at the fan to check
that it was actually spinning when I first installed it.

perhaps some people (including me) have
worried too much about case and PS fan noise.

I use Intel cpus mainly for that reason, the system is significantly
quieter. And I dont add extra fans either, I avoid hard drives that
get significantly hotter than average and dont run large numbers
of them in a single case either. Dont use gaming video cards either.

I do wish 120mm fans were used more
(more air yet lower RPM and noise).

Yep. The main reason they arent is that noise isnt a high
priority for most kids who dont seem to care if their system
sounds like its got a jet engine inside. Likely it makes them
feel like it must be a powerful system or something.

Rather like little kids zooming around
the house making engine noises |-)

No reason why a top, side or front fan can't be 120mm.
I like the idea of a top fan - that's where the heat goes.

But there isnt normally anything much up there
except the PSU and its got its own fan moving air
thru it. And people inevitably put stuff on the top too.

As I explained above, my fans are the same size after
all, but of course the PS has a more restricted airflow.

Yep, and thats what matters.

Anytime you have 2 fans in parallel both fans have
reduced air flow unless the chassis impedance is zero.

Thats just plain wrong. Its the total airflow out of the case that
matters and thats always increased when adding an extra fan.

Since it's not, you never get 2x the air flow (with equal fans).
Solution: size each fan to compensate
(or use more powerful fans and forgetaboutit).

Yep, that last is the real world, just ensure that the
total amount of air moved is what you require to
get acceptible temps in the cpu and hard drives.

Having a 2nd rear fan blowing in instead of out would
increase the air flow through the PS alright but it
would also reduce the total air flow through the case.

Sure, but what matters is ensuring that ENOUGH air is moving
thru the case to get acceptible cpu and hard drive temps.

Why not instead just make the PS fan bigger if need be?

Because that is constrained by the box the PSU is inside.

With new power supplies having 2 or even 3 fans now,

Few except the quiet supplys do.

having an extra rear fan blowing out (if you
still need one!) should be no problem at all.
Correct.

I agree. I want cooler outside air blowing in on the HD,
not hot inside air moving the other way (as I discover below).
Yep.

I was going by what Intel said, that fans in series
won't make much difference in air flow unless your
case has high impedance (which makes sense to me).

They're just plain wrong on that 'wont make much difference'

What you say above makes sense too, though I think it's not
"more air" as much as redirected air that gives the benefit.

Nope, when the cpu has its own fan and heatsink, it doesnt
need to be directed, what matters is the volume of air
moving thru the case as far as the cpu temp is concerned.

I decided to try it anyway by moving the rear
fan to the front (blowing in instead of out).

As expected it does increase the air flow through the PS
(even simply removing the side cover did that). But it's
cooking my HDs. Instead of running at 36C (HD mounted
in 3.5" slot) and 39C (5.25" slot), they're now running at 38C

That doesnt make any sense. And
that fan cant be blowing on that drive.

and 44-45C

Does that drive have bay cooling or not ?

(with no HD activity - I don't think I'd want to run a seek test now).

Yeah, no need with that signifcant hike, it can only get worse.

The front fan blows in but where does this air come from?

With a decent case it should be coming
in from outside. Likely it isnt with yours.

The bezel on my case allows the air to come from its bottom
edge or from any opening on the front of the frame, including
the wide open 5.25" slot used for the HD (once the cover is
broken off to allow installing the HD it can't be put back).

Yeah, thats the reason for that poor result.

So now, instead of the HD getting at least *some* cool
air from the outside, it's apparently being "cooled" with hot
air from the inside. The fan will be going back to the rear.

Sure, but that doesnt say anything useful about normal situations.

So if I replace the fans, which is better, the Vantec TF8025 temperature
controlled (1.8-2.8W) fan with an RPM monitoring cable, or the Panasonic
Panaflo with no RPM monitoring? I'm thinking the Vantec is better.

Yeah, safer to have a controlled shutdown on fan failure.

I gave the range that I've seen, 3-5. 3 hidden slots
(with a fan in front of them) would suit me fine (saving
maybe a dollar or two over having 5). I always have 2 drives

So why is one in a 5" bay ?

and it's nice to have room for one extra, even if
it's only used temporarily when upgrading a drive.

Sure but thats irrelevant to cooling when you wouldnt normally
bother to put the case cover back on in that situation.

And even with 1 HD it's nice to have good cooling.

What matters is what the SMART temp gets to.

 

[Timothy Daniels]

Now, have you actually performed the CFD on any
of this for a typical computer case or done a smoke test
or poked an anemometer into one, or are you just
stating an opinion?

...or spent 20 years around Experimental Aircraft Assoc.
activities; or read numerous publications on airflow
over/around/through airframes, instrumentation and engine
comparments; or helped a couple guys build homebuilt
aircraft; or have earned a pilot's license; or have worked
in the aerospace industry; or have a degree in physics;
or have futzed with my own PC? I dunno. Which do you
consider most important? What I contribute is some
understanding of basic sub-sonic fluid flow and thermal
management based on formal and informal study, without
any hardware sellers' "folklore" or Usenet trolling.


*TimDaniels*

 

[Timothy Daniels]

...I've learned my lesson though, next time I'm getting a
power supply with 2 or 3 fans....

"If More is Better, then Too Much is Just Right."
- old hot rodder saying regarding horsepower

I would apply the hot rodder principle in regards to PC
case cooling (providing you can stand the whoooshing
sound). I mean, you can only cool anything to the
temperature of the room, at best. Can room temperature
be too low for PC components?


*TimDaniels*

 

[Rod Speed]

John H wrote

That's the usual trouble with front fans and bezeled cases
- there are so many holes in the front that even if you seal the
fan shroud right up against the case, air can bypass the fan in
either direction. The only advantage to having a fan anywhere
near the front of such cases (either inside or outside the case
wall) is to add turbulence to the air impinging on the hard drive(s).

Mindlessly silly. Almost as silly as the other
stupid claim that using a drive bay cooler in the
5" bay stack will have any measurable effect on the
temperature of the drives in the main 3.5" bay stack.

Following the principle of directing interior air directly against the
face of hard drives without attempting to use fresh outside air

Terminally stupid approach.

are several cooling fans that can be referred to as "low
profile" hard drive fans. Here are just a few examples:
http://www.tigerdirect.com/applications/category/category_slc.asp?CatId=495

These fans just pressurize the air directly over the face of the hard drive

They blow air over the hard drive, stupid.

and allow the air to squirt out sideways,
parallel to the surface of the face.

Completely off with the fairys, as always.

Assuming that the interior air of the case in the vicinity of the
fans is lower than that of the hard drive, this will increase the
cooling effect over that obtained by simple laminar flow.

There is never any 'laminar flow' you silly little pig ignorant child.

I can't find the review now, but I recall reading
a review awhile back that found a worthwhile
temperature drop by use of such a "low profile" fan.

It'd be a hell of a lot more surprising if it
didnt drop you silly little pig ignorant child.

And thats got sweet **** all to do with whether
a much bigger fan in the bottom front of the case
that moves air from outside the case over the drives
would do just as good a thing for the drive temp, stupid.

AND be much less prone to fan failure if you use a decent fan too.

The advantage, of course, is not upsetting the overall flow
pattern within the case by not changing the interior pressure.

Completely off with the fairys, as always.

 

[Rod Speed]

John H wrote

"If More is Better, then Too Much is Just Right."
- old hot rodder saying regarding horsepower

Got SFA to do with PC case cooling, child.

I would apply the hot rodder principle in regards to PC case
cooling (providing you can stand the whoooshing sound).

More fool you. Anyone with a clue ensures that the
temperature of the cpu and the drives isnt anything
excessive and doesnt piss their money against the wall
moving any more air than is required to achieve that.

I mean, you can only cool anything
to the temperature of the room, at best.

Must be one of those rocket scientist children.

Can room temperature be too low for PC components?

Yes, but not too many would be stupid
enough to have the room temp that low.

 

[Timothy Daniels]

Incidentally, everything you list I've done. Plus grad school in
aeronautical engineering.

So?


*TimDaniels*

 

[J.Clarke]

So?

So why did you mention it?

 

[Timothy Daniels]

You can cool to well below room temperature....

Of course - if you're willing to resort to methods
other than moving room temperature air through
the case.


*TimDaniels*

 

[chrisv]

My PS is a 'let's do it the cheap way' "low noise" design. They simply used
one of the lowest powered 80mm fans available (.9W) and lowered the PS's
power rating from 300w to 275w. There is no thermal control, RPM
monitoring, dancing neon lights or any of that "fancy" stuff. I've learned
my lesson though, next time I'm getting a power supply with 2 or 3 fans and
every feature (except maybe for the lights ).

You sound like you think thermal control of fans is a bad thing? I
think it's by far the best way to do it. Otherwise you're just
guessing how much fan you need to keep things cool. And if you take
the "super safe" approach like you want to do, your PC ends-up
sounding like a vacuum cleaner. No thanks.

 

[lol]

So why did you mention it?

You guys are funny.

I used to work for a fan manufacturer. We used to do testing of
clients' boxes for thermal design. There's different ways to get the
same thing done (cooling). If you want to be einsteins, you can model
several different methods.

Most clients don't care.

There's usually some factor involved eg space, cost, noise, that
determines what they are going to do, not any sort of killer science.

You want to know how to cool your case ? get a cheap digital
thermometer and experiment.

Frankly, nothing else will do.

 

[Timothy Daniels]

There's usually some factor involved eg space, cost, noise,
that determines what they are going to do, not any sort of
killer science.

You want to know how to cool your case ? get a cheap
digital thermometer and experiment.

Good advice. But simple high school science (no "killer"
needed) will tell you where to begin, and it will tell you to
not even waste your time with things like "leaving the
covers off".


*TimDaniels*

 

[Louise]

Looks like its just Samsung not pushing them aggressively enough.



You should be able to find some canadian ones the same way.



There isnt a lot in it at the next level up. I'd got for
WD myself and avoid the Seagates and Hitachi/IBMs


The fans dont take enough to matter. I avoid
them for the other reason, the noise they make.

Why would you avoid Seagates? It is my impression they are
very quiet and very reliable - at least as of a year or so
ago. Have things changed with Seagate?

Louise