Cooling advice needed

[OppyLock]

Hi all,

Current specs:
P4C800-E, Zalman 7000A-cu atop a P4 3.0c @ 3.5Ghz, OCZ PC3700 Gold, ATI
AIW9800 Pro, Antec 480W supply, 2 x WD 200Gb SATA's non raid & 1x80Gb
Swap/Temp, usual assortment of readers/burners/floppies, Big yet generic
mid-tower case with 2 fans (1 in at front and 1 out from behind).

This has been housed in a PC sized cabinet, without a front door that is
built into my computer desk. There is a reasonable amount of space
surrounding the unit, especially above and behind. Probably 30cm behind and
above and about 10cm on each side. Airflow was always going to be iffy, yet
it hasn't been a problem until the ambient temps have crept up. It's
approaching summer here in Australia ya see.

The system used to idle at around CPU temp 32-36C and the stability limit
was reached around 50C. Now the idle has crept up to 40C and CPU OCing is
not feasible. Whether the system has the side panel installed or not
doesn't seem to have any impact, so I've left it on.

Computer room temps are about 26C at the moment and I expect them to easily
top 40C during summer. I shudder to think what the 'in system' temps will
be then.

I've toyed with the idea of plumbing the exhaust fan direct to the outside
of the cabinet ... has anyone else tried something like this successfully?

I've toyed with the idea of ditching the fancy computer desk for one that
leaves the PC exposed to the nice cool air ... but I do like the desk. It's
got nice wrap-around edges to help keep 'stuff' handy and holds all the
peripherals withn easy reach. Two monitors, printer and scanner, plus
cameras and paperwork take up a fair bit of desk real estate.

I've also been looking at external water cooling options, but they make
travelling for a LAN party an onerous task. It's bad enough now having to
secure the Zalman before transporting the box.

Anybody else got any ideas to help cool it down.

Cheers,
Anthony

 

[Paul]

Hi all,

Current specs:
P4C800-E, Zalman 7000A-cu atop a P4 3.0c @ 3.5Ghz, OCZ PC3700 Gold, ATI
AIW9800 Pro, Antec 480W supply, 2 x WD 200Gb SATA's non raid & 1x80Gb
Swap/Temp, usual assortment of readers/burners/floppies, Big yet generic
mid-tower case with 2 fans (1 in at front and 1 out from behind).

This has been housed in a PC sized cabinet, without a front door that is
built into my computer desk. There is a reasonable amount of space
surrounding the unit, especially above and behind. Probably 30cm behind and
above and about 10cm on each side. Airflow was always going to be iffy, yet
it hasn't been a problem until the ambient temps have crept up. It's
approaching summer here in Australia ya see.

The system used to idle at around CPU temp 32-36C and the stability limit
was reached around 50C. Now the idle has crept up to 40C and CPU OCing is
not feasible. Whether the system has the side panel installed or not
doesn't seem to have any impact, so I've left it on.

Computer room temps are about 26C at the moment and I expect them to easily
top 40C during summer. I shudder to think what the 'in system' temps will
be then.

I've toyed with the idea of plumbing the exhaust fan direct to the outside
of the cabinet ... has anyone else tried something like this successfully?

I've toyed with the idea of ditching the fancy computer desk for one that
leaves the PC exposed to the nice cool air ... but I do like the desk. It's
got nice wrap-around edges to help keep 'stuff' handy and holds all the
peripherals withn easy reach. Two monitors, printer and scanner, plus
cameras and paperwork take up a fair bit of desk real estate.

I've also been looking at external water cooling options, but they make
travelling for a LAN party an onerous task. It's bad enough now having to
secure the Zalman before transporting the box.

Anybody else got any ideas to help cool it down.

Cheers,
Anthony

This web page has a nice formula for working out CFMs required.

http://www.chassis-plans.com/cooling_and_noise.html

CFM = 3.16 x Watts / allowed temp rise deg F

Using round numbers, 100W CPU, 60W Video, 12W per drive x 3 = 200W.
The PSU will be roughly 70 percent efficient, and so the PSU adds
another 86W to the heat load. Using 286W, and 12.6F max case temp
rise (as recommended by AMD), this gives a pessimistic estimate of
72CFM. (This only happens while gaming. Sitting idle in the desktop,
I've measured my CPU, a 2.8 Northwood, at only 13W power
dissipation. The video card will be around 30W at idle. So, if this
is an office computer that doesn't run 100% CPU for long periods,
you could live with less air flow.)

What you could try, is underclocking for the summer. Dropping the
FSB on the processor should reduce the power somewhat. Dropping
the FSB will work better with a Northwood, than with a Prescott, due
to the leakage current increasing with each generation of silicon
technology. Replace the video card with a ATI9000 or FX5200 style
video card, and the computer will run a lot cooler. It just means
no gaming during the summer, if you want to keep your current
chassis arrangement as is.

Disk drives and the PSU are the weakest links, when it comes to
temperature. Disk drive life is affected by both temperature
and humidity, and even 35C/60% humidity is bad for a drive. You
might try tracking down the OEM manual for your drives, as some
disk drive manufacturers include a temp/humidity chart that gives
allowed conditions for the drive. The PSU is also affected, as
the max PSU output allowed, drops with temperature. See this
advert, for a sample curve:

http://www.pcpowerandcooling.com/pdf/Turbo-Cool_510_vs.pdf

Can you actually sit in front of that computer, at 40C, and
do anything constructive ? As I'm a cold blooded Canadian,
there would be nothing left of me but a puddle of sweat at
that temperature. I hope its a dry heat.

HTH,
Paul

 

[Ghostrider]

Comments are in-line.

OppyLock wrote:

I've toyed with the idea of plumbing the exhaust fan direct to the outside
of the cabinet ... has anyone else tried something like this successfully?

Good idea. The issue is more of airflow and with a vent,
there is a flow of air instead of standing air.

I've toyed with the idea of ditching the fancy computer desk for one that
leaves the PC exposed to the nice cool air ... but I do like the desk. It's
got nice wrap-around edges to help keep 'stuff' handy and holds all the
peripherals withn easy reach. Two monitors, printer and scanner, plus
cameras and paperwork take up a fair bit of desk real estate.

Better idea. Keep the desktop and ditch just the cabinet
that is housing (er, enclosing) the computer. Some computer
cases look pretty attractive these days, esp. with the
neon lighting, such as the full-tower Thermaltake Xasers
or Tsunamis.

I've also been looking at external water cooling options, but they make
travelling for a LAN party an onerous task. It's bad enough now having to
secure the Zalman before transporting the box.

If one thinks about water cooling, then try using a
Peltier cooling solution first. But not recommended
due to potential wetting (e.g., via condensation or
even a coolant leak).

As for going to a LAN party, get a desktop replacement
type of laptop. Well worth it.

HTH & GL.

 

[OppyLock]

This web page has a nice formula for working out CFMs required.

http://www.chassis-plans.com/cooling_and_noise.html

CFM = 3.16 x Watts / allowed temp rise deg F

Using round numbers, 100W CPU, 60W Video, 12W per drive x 3 = 200W.
The PSU will be roughly 70 percent efficient, and so the PSU adds
another 86W to the heat load. Using 286W, and 12.6F max case temp
rise (as recommended by AMD), this gives a pessimistic estimate of
72CFM. (This only happens while gaming. Sitting idle in the desktop,
I've measured my CPU, a 2.8 Northwood, at only 13W power
dissipation. The video card will be around 30W at idle. So, if this
is an office computer that doesn't run 100% CPU for long periods,
you could live with less air flow.)

What you could try, is underclocking for the summer. Dropping the
FSB on the processor should reduce the power somewhat. Dropping
the FSB will work better with a Northwood, than with a Prescott, due
to the leakage current increasing with each generation of silicon
technology. Replace the video card with a ATI9000 or FX5200 style
video card, and the computer will run a lot cooler. It just means
no gaming during the summer, if you want to keep your current
chassis arrangement as is.

Disk drives and the PSU are the weakest links, when it comes to
temperature. Disk drive life is affected by both temperature
and humidity, and even 35C/60% humidity is bad for a drive. You
might try tracking down the OEM manual for your drives, as some
disk drive manufacturers include a temp/humidity chart that gives
allowed conditions for the drive. The PSU is also affected, as
the max PSU output allowed, drops with temperature. See this
advert, for a sample curve:

http://www.pcpowerandcooling.com/pdf/Turbo-Cool_510_vs.pdf

Can you actually sit in front of that computer, at 40C, and
do anything constructive ? As I'm a cold blooded Canadian,
there would be nothing left of me but a puddle of sweat at
that temperature. I hope its a dry heat.

HTH,
Paul

Thanks for all that Paul. Very helpful indeed.
I'm definately underfanned at the moment. The new plan is to seal the
original case airvents, as they're not placed very well. I've drilled out
two new ones into the bottom of the case and two into the top. I'll cut out
a panel in the floor of the cabinet which will allow it to suck in coolish
air from underneath the desk. I'm not sure how this'll work out, but I'll
also use some flexible pipe to connect the exhaust fans to the upper side of
the cabinet.

So, going from 2 badly placed fans to 4 good ones should help somewhat.

I don't plan on sitting in front of the PC much this summer, although
half-life 2 may change that ... even at 40C I may just need to do it.
I've got an old evaporative cooler that I could wheel in there, but it's
probably not a good idea to really over humidify the environment with it. A
couple of human sized fans might be the go.

The PC will be on most of the time regardless as it's got a wide variety of
domestic chores to fill its days ... It's a busy box.

Cheers,
Anthony

 

[OppyLock]

Comments are in-line.

OppyLock wrote:



Good idea. The issue is more of airflow and with a vent,
there is a flow of air instead of standing air.

See other post. I've doubled the fans and placed then more optimally.
Doesn't seem to make any more noise than it used to - Bonus !!

Better idea. Keep the desktop and ditch just the cabinet
that is housing (er, enclosing) the computer. Some computer
cases look pretty attractive these days, esp. with the
neon lighting, such as the full-tower Thermaltake Xasers
or Tsunamis.

I wish I could. The cabinet is an integral part of the structure of the
desk. The missus won't let me get a new desk either, as THIS desk is the
new one. I only bought it about 1 year ago. So I'm sorta stuck with it.

If one thinks about water cooling, then try using a
Peltier cooling solution first. But not recommended
due to potential wetting (e.g., via condensation or
even a coolant leak).

As for going to a LAN party, get a desktop replacement
type of laptop. Well worth it.

HTH & GL.

The more I look into alternative, ie not air-cooled heatsinks, the worse the
picture becomes. Just waaay too impractical.

On the bright side though the boss has just given me a shiny new NEC E2000
to replace the partly working NEC Versa VX that I had been using for work.

Cheers,
Anthony

 

[Peacekeeper]

Some extra thoughts

1. I wonder if you have checked the heatsink ?My last check of mine showed
the fins chockers with fluff even though all 4 inlet fans are filtered. I
have 4 outlet as well all quiet fans so noise not an issue. Repositioning
the fan inlet low down and outlet highup helps somewhat but you need to move
the exhausted air away from the case surrounds.

2. Re ducting check auspcmart they have flexible ducting for fans you maybe
able to direct outlet air away from the enclosure.

My heat issue now solved got aircon in computer room now so temps kept at
22C

Peace