Building Linux Appliances - Dealing with Heat Issues? 25
wyrfel asks: "I'm going to build a router & switch based on LRP on the software side and on a FIC PA-2005 with Pentium 200 on the hardware side. Having read some discussions and wanting to make the system as quiet as possible I've remove everything except the floppy (which will be removed once the system is up an running), CPU and RAM from the board, lowered the boards speed from 66MHz to 50MHz which brought down CPU speed to 150MHz, did cut of the power supplys fan and lowered voltage of the CPU fan to 5V instead of 12V. So far everything seems to work fine. The power supply gets a bit warm on the top but it seems to be ok. I didn't add any PCI / ISA cards yet, so I wonder if doing so would bring problems through higher power consumption. What I really worry about is the heatsink that is placed directly beneath the CPU heatsink and that gets a bit hot when running the CPU fan with 5V. With 12V it's fine because of the extra airflow that comes from the fan located near that heatsink. BTW it is attached to some tiny piece labelled 'LINFINITY LX8382A'. Can someone tell me if I have to worry about it becoming too hot and if so what means 'too hot'? Any hints or further suggestions?"
If it's a Pentium, I wouldn't worry about heat (Score:2, Funny)
Unless you're clustering a bunch of these in a small space, it should be fine.
Re:If it's a Pentium, I wouldn't worry about heat (Score:2)
At the time, this was seen as a sign of poor chip design
Re:If it's a Pentium, I wouldn't worry about heat (Score:2)
If you can still touch it for 5 seconds w.o pain (Score:3, Funny)
I mean, it's not fair to ask your CPU/etc to go through something you wouldn't do yourself.
Be careful though, I once got a blister on my right index finger from a P3 heatsink with a failed fan, couldn't write for days
Beware the dust puppy! (Score:1)
I have built a router out of a P75 (oc'ed to 90 MHz!), but I recently lost its IBM harddrive. When I opened the case, I it was full of an inches-high structure of dirt. Most probably, the bad ventilation of the case caused the dust to accumulate which in turn prevented heat circulation and contributed to overheat the fragile drive.
The morale of the story is twofold:
Actually (Score:1)
When the chip becomes hot, the data paths on the chip become longer (heat expands things) and the data expected to be coming out of the chip at the end of that clock cycle might not be accurate.
The best way to test the thing is to wait til it gets about as hot as you think it's going to get, and then start feeding it complex math equations (which you presumably would know the correct answer to). If they turn out correct, you can assume its operating within spec.
Re: (Score:2, Informative)
Voltage regulator (Score:1)
I would try mounting the fan so that more air flows across the regulator heatsink, or get another board with a switching regulator.
had router with fli4l (Score:1)
Ditch the old hardware (Score:3, Insightful)
There are a large number of recent motherboards with NIC's on-board and low-heat CPU's (like the Via C3) widely available right now for really little $ if you want a PC-clone (e.g. ATX) form factor solution.
If you want even more reliability and efficiency, along with very much improved configurability, ditch the ATX stuff completely and go to PC/104.
Or - best of all - ditch the heat-hogging Intel-compatibles and go with a true low-power embedded CPU. See the usenet newgroup "comp.arch.embedded" and get up to speed :-)
Re:Ditch the old hardware (Score:2, Interesting)
When I get everything configured, I plan to replace the hardware. Via just released the EPIA 5000 and 800 boards. The Epia 5000 has on board LAN, sound, and video. The CPU is not speedy, it's about the speed of a P233, but requires no active cooling. The total is $98 [64.186.164.229]. You can't upgrade anything (CPU is surface mounted) and you only get one PCI Slot. But, depending on what you're doing, it can fit the bill. If you need more speed, $10 more gets you the Epia 800 (though it needs a small fan). If you need more power/PCI slots, you can upgrade to using a Micro-ATX board and use a VIA C3 (also needs minimal cooling)
You can get a Mini-ITX case w/ the power supply external [64.186.164.229] (so no heat inside the case, and still no fan) for $72 (of course there are other neat cases [64.186.164.229]). Toss in some memory, a network card, and some disk and you're done. I'm just going to put in a normal HD, it shouldn't be used much. If it makes too much noise I'll replace it with a laptop drive or a baracuda.
I'm going to add a USB-Ethernet adaptor ($5) so I can segment off my wireless base station. It should be more than fast enough to keep up (I'll know next week). I'm still looking for a working OS X VPN solution. I want to firewall off the wireless and use a VPN to get though the firewall. I might have to wait for Jaguar for that. Then I could use IPSec (hopefully the Epia 5000 is fast enough to handle IPSec over wireless.).
While this costs more than what you've got lying around, it's more than fast enough for a router and it'll be totally silent.
Lower the CPU multiplier, not only the FSB (Score:2)
Re:Lower the CPU multiplier, not only the FSB (Score:1)
Re:Lower the CPU multiplier, not only the FSB (Score:1)
Quiet fan. (Score:2)
I'm also confused about the "heatsink under the heatsink" comment. Do you have stacked heatsinks????? WTF?
On some old (Micron) pentiums, they were using Massive heatsinks instead of fans. You would want to make sure that the fins are oriented vertically. Have vent holes in the bottom and top of the case (heat rises ya know..) If you are using a really small case, you may need a fan just due to the density inside the box. The samller cases had problems with heat buildup.
you worry too much (Score:1)
It had 1 pci nic and 2 ISA (I was using it as a hub)
It ran fine for months until I finally found a great 12 port 10 mb/s hub in a dumpster. (Yes, I'm poor =)
LX8382 (Score:1)
Want to catch the house on fire? (Score:3, Insightful)
Bump cpu fan speed by 2 volts (Score:1)
See http://www.overclockershideout.com/7voltmod.shtml [overclockershideout.com]
www.soekris.com (Score:1)
For small routers/firewalls (and if you don't mind spending a modest amount of money), check out the small PC-compatibles from Soekris Engineering [soekris.com]. Their (well, his) main product is a small PC-compatible board designed for routers/firewalls: a 133MHz 486 class processor (AMD ElanSC520), 64MB RAM, three (3) LAN ports, a type II compact flash socket, BIOS, and a serial console port. Note that there's NO video, sound, or IDE ports (you boot from LAN or from the compact flash port, which can be used with an IBM microdrive). It's low power (under 20 watts), very quiet (no fans), and pretty small. Cost with metal case and US wallwart power supply is something like $250 plus tax and shipping (bare boards are available, too). In the past, availability has been a bit intermittent ("in stock" maybe once a month), as they seem to sell out their incoming production batches fairly quickly, so be warned.
Also, I believe that they're about to ship a version with PCMCIA slots (but only two LAN ports), basically designed for people to build wireless access points/firewalls.
People have FreeBSD and Linux (I think) currently running on it. I bought one to create a FreeBSD-based home firewall, and it's pretty cool (I haven't yet deployed mine, but I'm getting close). There's also a mailing list (check out the web site).
However, if you need video, sound, or IDE ports, one of the Shuttle boxes might be a better match (although they'll probably use up a lot more power).
VIA's Eden x86 Platform (Score:2)
p133 runs fine for me (Score:1)
Anyway the box now runs with 3 realtek pci nics and floppyfw w/o any problems.
I think u can remove the fan from your cpu and replace it with some real big metallic cooler like the Mac G4 machines have inside. dunno where to get such things though (from old compaqs, hehe).