who has a stable fanless cpu?
what passive heatsink do you use to coll it?
is it undervolted?

I know that via c3, celeron 466 can be used with a passive heatsink

I used to run a Celeron 600 fanless. I unplugged the fan, and used the retail HS that came with it. I also undervolted the CPU to 1.4V instead of 1.5V. It was running on a slot kit on an Abit BH6. I ran it for a year 24/7. It was flawless. Its still running right now in another machine (but I have the fan on since I put it in a place in my house where I don't care about noise).

So, if one put a larger heatsink (i.e. a volcano 5 or something)... I'm sure the Cel 600 would run fine.

For me, the Via c3 800mhz ezra core, w/ volcano 6 hs, runs fanless no problem. Case airflow provided by one 80mm panaflo undervolted (in the PSU).

http://it9.net/quiet/v6.jpg

I spread the fins out like a zalman for good measure, but i dount it is necessary.

I like that. Looks like a Zalman knock-off

Its a good idea though!

I'm still using passive heatsink with TB1400@1326, 1,45V, maximum temp 65 C and usual temp 59 C:

Very cool bluehat. What kind of heatsink(s) is on the cpu, and what are the other heatsinks that we see in the picture? Also, I am curious how you are measuring the temps on your cpu. Note the huge discrepency that was found between socket temps and actual core temp as shown in the 4-heatsink roundup here at SPCR. 65C might be pushing it temperature wise if thats a socket diode reading, but if its stable and it doesnt ever get hotter, then more power to ya!

update: found answers to my questions--http://members.fortunecity.com/bluehat1/heatsink.html

good stuff bluehat, keep up the good work.

I forgot to mention I also have a fanless P3 667 slot-1 (133 FSB) chip on an abit VT6X4. Only fan in that machine is the poweruspply fan.

The heatsink is not a regular slot-1 though. IT has pretty large fins. I think its one of those Dell supplied ones... But I put a probe on it and it seemed to peak at at a steady 35oC on the heatsink for a good hour. So it seems pretty good

the heatsink that bluehat uses seems to be less efficient than zalman 6000, so the temperatures could be even better


to bluehat: where did you buy that heatsink?

I bought it from a local electronc shop. It has a thermal resistance 0,40 C/W without any fans. Zalman is not even telling their heatsink's real thermal resistances.

System temp is a bit high (39 C) because there is no case fans.

I accidently ran a P3 800 for several days without any fans and with a stock heatsink. The sink was warm to the touch, but not hot. I would definitely consider getting a later model P3 and clocking (if possible) back down to 800.

-C

I discovered that I had been running my Athlon 750 for about a month without any problems fanless. It was quite a surprise when I opened my case to upgrade my soundcard and I noticed that my CPU fan was not spinning. One of the leads had let go of my home-made fanbus. (note, this was a modified stock AMD HSF - I replaced the noisy 50mm fan with a quiet 80mm fan, and attached it with dental floss)

What surprised me the most was that the CPU had been running just as stablely without the fan as it had been before. Turns out that the box I was running had adequate cooling without it. (One intake, one exhaust - both panaflo's - and a powersupply fan)

Needless to say, I re-attached the fan for safetey's sake, but lesson to be learned is that if you're going for extreme cooling, you might not even need the fan if you're not doing anything hardcore with your CPU.

Got a slot 1 Pentium II 450Mhz running fanless with the retail heatsink for a year now 24/7 without problem.

The PSU fan is 7V. Have another 5V fan blowing my 80G Barracuda IV, which is placed on soft form at the bottom of the case.

I can only hear it at the middle of the night.

I have my Duron 700 unlocked and running @ 500 Mhz (5x100). i undervolted it to 1.3 volts however i believe it can be set lower without making the system unstable.

The heatsink i use is an Alpha 6035 and according to my motherboard sensor it's running at 40c, this seems high but one time the BIOS settings where on accident reset and the thing was running at 700Mhz with 1.6 volts without ANY active cooling

After a while i discovered the tempature was 78c degrees !

I quickly shut off the damn thing but after this "burn-in" the cpu temperature is 40c whereas previous it was like 32c....i think the diode is kinda messed up..

I was really surprised it survived without active cooling at 78c ?! i think the alpha heatsink really helped me here.
The only active cooling is on the north bridge (KT7a) but this fan is running at 7v and you can't hear it.

I've run a Slot 1 Pentium III 1GHz CPU fanless on a server 24/7 before, but it underclocked to 75Mhz FSB. No undervolting because the motherboard didn't support it.

Admittedly, the server doesn't see much 100% cpu time, but it worked out very well.

Don't know what brand of heatsink it was, but it was taller than the Slot1 CPU itself by about an inch and the fins were about 3/4 of an inch in well spaced grid pattern.

I believe the CPU temperature reading in the BIOS screen peaked out around 50C.

been running my k6-2 500 at 300 fanless for the past couple of weeks. At 1.9V as opposed to the 2.2V standard. Has the stock heatsink on it. Not sure wat it is cause its so old.

being used as a mp3 box. more than adequate power

Those with a fanless CPUcooler and casefan and/or a dualfan PSU might try to make ducts or similar to guide the airflow created by theese fan over your cpu-fan

Like this :
http://216.239.39.120/translate_c?&u=ht ... 73_s4.html

The link is to a fanless CPU heatpipe cooler - Looks interesting , though I can find several points where the design could be improved.

I've got dual P3/450's passively cooled in my server...they barely even get warm.

Pete

I now qualify:

P55C 233MHz on Atrend ATC-5000MB in AT case.
1" high Coolermaster heatsink, with fan removed, on CPU.
Enermax 80mm adjustable sucker in front at minimum RPM.
Deer 230W AT PS blowing out the back.
CDRW, 40GB 7200RPM HD, Floppy.
VGA, Sound, and Ethernet cards, 160MB RAM.

The CPU heatsink runs at about 120F while running Prime95 with the case open in a ~65F room.

Now maybe I need some Panaflo's for the Case and PS

JV