• Welcome to Overclockers Forums! Join us to reply in threads, receive reduced ads, and to customize your site experience!

Can I use passive cooling on a P233

Overclockers is supported by our readers. When you click a link to make a purchase, we may earn a commission. Learn More.

DaWiper

Image Compare Man
Joined
Nov 15, 2003
Location
Norway
I'm thinking of putting together a gateway/firewall of a old pentium 233. It has to be quiet cuz it will be on 24/7.
If I get a large heatsink and no fan, will it be enough to cool the cpu?
 

repo man11

Member
Joined
Dec 28, 2001
Yes. I had an old Dell with a P200 that came from the factory with a large heatsink with no fan. It worked fine.

As listed at Sandpile.org, typical power for the P55 is less than 10 watts. Far less than any modern CPU.
 

eobard

Give me a break Senior
Joined
Jul 12, 2001
You might want to look into underclocking and undervolting it if it's only going to serve as a firewall, my firewall is a P1 133 and its fine for that task.
 

Glaze132

Member
Joined
Oct 27, 2002
Location
Las Vegas, NV
I have a K6 300MHz that was sold passively cooled and still works fine to this day and the psu fan was the only fan in the entire system and that thing isn't even loud either. But I don't use that machine anymore, it is just to slow. I'm betting you could do the same with a cheap hs for you 233MHz cpu.
 

sandman001

Just Freeze It
Joined
Mar 11, 2003
My P3 500 is passive, straight from gateway this way.

Runs a bit warm, but then I added a case fan it cooled it back down.
 
OP
DaWiper

DaWiper

Image Compare Man
Joined
Nov 15, 2003
Location
Norway
Ok, maybe I'll try with a nice big heatsink and a thermal probe... Think it will work just fine. If I just coul figure out how to kill the psufan noise...
 

eobard

Give me a break Senior
Joined
Jul 12, 2001
I use diodes to lower the voltage on my fans. A 1N4001 diode will shave .7v off and a 1N4002 (which I use because I can't get the 4001's locally) will shave .3v off of your fan's 12v. I run 5 in series and lower the voltage of my heater core's fan to 10.5v and it's a lot quieter. You can see in the pic below what I've done.

#1 is where the mini molex (for floppy drives) connects to the board

#2 is the jumper that lets me choose between full voltage or full voltage -1.5v

#3 is the output for the fan

#4 is a jumper for the molex's 5v line just incase I need it for something else

It'd be a lot simpler to make a circuit like that that doesn't have as many diodes and doesn't need the jumper part. Just splice into the live feed for the PSU's fan and solder inline two or three diodes, you don't even need a circuit board for that. Make sure you heatshrink the whole deal though, you do not want a short in your PSU!
 

Attachments

  • diodes.jpg
    diodes.jpg
    19.7 KB · Views: 83

sandman001

Just Freeze It
Joined
Mar 11, 2003
That seem slike kidn of a pain to do that, While it may be more expensive, I'd just get a fan controller.
 

cmonkey

Registered
Joined
Jun 20, 2003
You can run a p233 with no fan. I had a p233 that had a tiny heatsink with a 40 mm fan on it. The fan died without me knowing about it a long time ago. It hasn't overheated, and it has remained rock-stable. Earlier this year, it had an uptime of 6 months. (it went off during that big blackout). So, there should be no problems at all as long as there is some sort of heatsink on the thing.
 

Startech

Member
Joined
Dec 4, 2003
Location
DFW
Get a nice big heatsink and go for it. If it shortens the life of the CPU, so what? Get another one for nothing. Not like if it was a 2.4c M0! :p
 

Cyberwiz01

Member
Joined
Jul 3, 2003
Location
hunting wolverines
that cooler should be more than enough, like it says above, a Pentium 1 won't put out very much heat. The northbridge on most modern boards probably puts out about as much heat as an old pentium.
 

flixotide

Member
Joined
Oct 29, 2002
Location
Denmark
I've had several passive cooled P1-233. The Slot-1 P2-233 however was harder to keep cool.

So before I say, YES you can, I would need confirmation that you are talking about the old Pentium 1 - 233.

Is it with or without the MMX? The MMX series grow warmer though. But it should not be an issue.

Cheers, Flix
 

Korndog

Member
Joined
Nov 30, 2002
Location
California
my friend has a huge copper passive heatsink on his althon tbird 1.3ghz with on case fan blowing air out.
run about 55c and he doesn't mind
if it can be done with a 70+watt CPU, then it can be done with a ~25watt cpu like urs, lol
 

Korndog

Member
Joined
Nov 30, 2002
Location
California
ok i'm a moron, my 450mhz data/pinter server computer has a stock passive heatsink on it, only psu fan, stock from toshiba, been running for years like that so if it can do it a p233 can fo sho
 

L337 M33P

Member
Joined
Jun 5, 2003
Location
TEH INTERNETS
eobard said:
I use diodes to lower the voltage on my fans. A 1N4001 diode will shave .7v off and a 1N4002 (which I use because I can't get the 4001's locally) will shave .3v off of your fan's 12v. I run 5 in series and lower the voltage of my heater core's fan to 10.5v and it's a lot quieter. You can see in the pic below what I've done.


The 1N400* series are all bog-standard silicon rectifiers - the number after the 400 bit is just the voltage rating. A silicon PN junction always drops 0.7V, so that ain't right. 1N4002s should also have a forward voltage drop of 0.7v. The only types that have drops lower than this are Epitaxial or Schottky barrier diodes, and even then they are 0.5v.

Good idea to use diodes though...