Passive cooling for 486dx4

[level13]

Pretty much dissatisfied with what the out-of-box routers/firewalls are
offering, I decided it's finally time for me to reinstate an old 486
box to serve as the first line of defense and traffic routing in place
of a LevelOne box.
However... Due to its location it is imperative that it's completely
silent. I don't care much about the hard-drive's noise (in case I do
decide to use it instead of a floppy or a flash card on flash-to-IDE
adapter) - but rather about the other two moving parts: CPU fan and PSU
fan. My questions are -- can this CPU survive with a passive cooler
only? If so, which one(s) do you recommend? How about PSU -- which one
to use (hopefully not some pricey one)?
The specifications are: 486dx4, 100 MHz, 32 MB RAM. For system+storage
I'll either use a floppy, a CD, or a flash memory card.

 

[Ghostrider]

Pretty much dissatisfied with what the out-of-box routers/firewalls are
offering, I decided it's finally time for me to reinstate an old 486
box to serve as the first line of defense and traffic routing in place
of a LevelOne box.
However... Due to its location it is imperative that it's completely
silent. I don't care much about the hard-drive's noise (in case I do
decide to use it instead of a floppy or a flash card on flash-to-IDE
adapter) - but rather about the other two moving parts: CPU fan and PSU
fan. My questions are -- can this CPU survive with a passive cooler
only? If so, which one(s) do you recommend? How about PSU -- which one
to use (hopefully not some pricey one)?
The specifications are: 486dx4, 100 MHz, 32 MB RAM. For system+storage
I'll either use a floppy, a CD, or a flash memory card.

It has been a very long, long time since last seeing one of these
set ups. But AFAIK, it should be possible to run the 486DX4 CPU
without a CPU fan provided that there is adequate volume around
a very efficient heatsink for passive convectional cooling. And as
for the PSU, good luck on chasing down an AT unit. And, finally,
keep in mind that the technology relating to the i486 CPU era is
far different from that available today. Good luck!

 

[philo]

Pretty much dissatisfied with what the out-of-box routers/firewalls are
offering, I decided it's finally time for me to reinstate an old 486
box to serve as the first line of defense and traffic routing in place
of a LevelOne box.
However... Due to its location it is imperative that it's completely
silent. I don't care much about the hard-drive's noise (in case I do
decide to use it instead of a floppy or a flash card on flash-to-IDE
adapter) - but rather about the other two moving parts: CPU fan and PSU
fan. My questions are -- can this CPU survive with a passive cooler
only? If so, which one(s) do you recommend? How about PSU -- which one
to use (hopefully not some pricey one)?
The specifications are: 486dx4, 100 MHz, 32 MB RAM. For system+storage
I'll either use a floppy, a CD, or a flash memory card.

With a large enough heat sink...a fan should not be needed for the 486...

to ensure a cool cpu , you may even want to clock it down to maybe 66mhz or
so

as far as the psu, a fan probably is needed, though you might get enough
cooling if you ran the fan at a lower
voltage

 

[Rod Speed]

It has been a very long, long time since last seeing one of these
set ups. But AFAIK, it should be possible to run the 486DX4 CPU
without a CPU fan provided that there is adequate volume around
a very efficient heatsink for passive convectional cooling.

I did it fine with a 586 which was one step up from the 486DX4.
Didnt need anything special passive heatsink wise.

And as for the PSU, good luck on chasing down an AT unit.

There's plenty on ebay and in discards.

And, finally, keep in mind that the technology relating to the i486 CPU era is far different from
that available today.

But still quite viable for that particular use.

Good luck!

He wont need that.

 

[Paul]

Pretty much dissatisfied with what the out-of-box routers/firewalls are
offering, I decided it's finally time for me to reinstate an old 486
box to serve as the first line of defense and traffic routing in place
of a LevelOne box.
However... Due to its location it is imperative that it's completely
silent. I don't care much about the hard-drive's noise (in case I do
decide to use it instead of a floppy or a flash card on flash-to-IDE
adapter) - but rather about the other two moving parts: CPU fan and PSU
fan. My questions are -- can this CPU survive with a passive cooler
only? If so, which one(s) do you recommend? How about PSU -- which one
to use (hopefully not some pricey one)?
The specifications are: 486dx4, 100 MHz, 32 MB RAM. For system+storage
I'll either use a floppy, a CD, or a flash memory card.

I found a datasheet, and the power is around 5W max for the processor.
For a Northbridge style heatsink, something around 2 inches high or higher
might work. Or select some other form factor of heatsink which fits. It
all depends on the mounting holes available, as to what might make a good
convection cooler. But the 5W suggests it is doable with some
care.

For a PSU, there are some fanless ATX units, but they are expensive.
There are some power configs, consisting of a pico power converter
and laptop adapter, but that is probably still expensive, considering
the small amount of power you get. And you'd need to adapt a device like
this, with cabling suitable for your motherboard - it likely won't
fit as is.

http://www.mini-itx.com/store/?c=10#picoPSU

Newegg carries one of the lower power versions of those kits. Your
machine's total consumption might be quite a bit more than this
can handle. To use low power gear like this, you really need to
drive the system with a regular supply first, measure consumption
under realistic max load, then figure out what size Pico might work.
And for all the hassle, a fanless ATX regular supply makes as
much sense.

http://www.newegg.com/Product/Product.asp?Item=N82E16813995001

Here is a fanless ATX. Currently listed as out of stock. May well
be $100 when they get some more. You'd probably need adapter
cabling, to convert from ATX cable to whatever your motherboard
uses. Supplies like this make the most sense, when you are
well under their "rated" power.

"FSP Group (Fortron Source) ZEN FSP300-60GNF-R ATX 12V Version 2.0 300W Fan Less"
http://www.newegg.com/Product/Product.asp?Item=N82E16817104902

Paul

 

[nobody]

My questions are -- can this CPU survive with a passive cooler
only? If so, which one(s) do you recommend? How about PSU -- which one
to use (hopefully not some pricey one)?
The specifications are: 486dx4, 100 MHz, 32 MB RAM. For system+storage
I'll either use a floppy, a CD, or a flash memory card.

I had a 486DX33 that had no heatsink or fan. The DX66 had a heatsink
only, and the faster models had fans as I recall.

I'd just use thermal epoxy to glue on the biggest heatsink I could
fit on it. I'd think the Thermalright motherboard chipset
heatsinks would work great.

If the cpu dies, pick up another for six bucks.

 

[Rod Speed]

(e-mail address removed) wrote

(e-mail address removed) wrote

I had a 486DX33 that had no heatsink or fan. The DX66
had a heatsink only, and the faster models had fans as I recall.

Nope, the 586 worked fine with just a heatsink, no fan.