Building an Energy Efficient, Always-On PC? 155
An anonymous reader asks: "Like many readers, I find it necessary to leave my home PC running 24/7, for things like web or FTP servers, BitTorrent, or simply to make sure I don't miss any messages on IRC or my instant messaging client. It has been about 3 years since I built my current PC, and keeping it running all the time uses a lot of juice. With my next PC, I would like to do what I can to keep the power-consumption to a minimum, without sacrificing processing power or other features. What should I look for when choosing components for my PC, and what other ways are there to keep the power consumption down?"
Dont bother. (Score:2, Interesting)
Generally the energy expended into making a product is directly relative to its price (see Marx and Aristotle). Whether the product is fantastically overpriced and the profits are used to fly CEOs around the world in personal jets, or if the product is made in a sweatshop where the workers are obviously not earning that much and have a greatly smaller carbon footprint than others. Every cent you spend is in turn spent on
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So, a more expensive solution that uses less power, and thus ends up costing less in total, over the lifetime of the PC, will likely also be more environmentally friendly. It'd be better for your electricity-bill too.
At $0.15/kwh, saving 50W (say going from 100W average to 50W average) is worth $65/year in a always-on device. So, if such an always-on home-server is used for 3-4 years, that sav
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It also depends on how the power is used. If it's being used in the CPU, it's going to kick out a lot of heat
Actually it doesn't matter where it's being used, in the CPU or elsewhere, every watt into your computer is going to end up heating your house.
If your system is using less power, it's also probably kicking off less heat. If you're in Florida like me, you should pay attention to that, considering most Floridians air condition for 10-11 months out of the year.
OTOH, if you live where you have to heat your house a large part of the year, the heat it gives off may offset the energy cost. In my case it's a little more expensive to heat with electricity than with natural gas so the energy into the computer isn't free, but the heat does effectively reduce the cost a little.
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Not _every_ watt. Most watts. Things like light and sound going out the window don't heat the house; they're pretty negligible power-wise, but I wouldn't be too surprised if a few watts from a wireless card heat the outside world rather than your house.
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Actually, no. It does not matter where the power is being used. All of it turns into heat regardless.
Yes, but not all of that heat is helpful to me. The photons leaving my monitor that escape through the glass of my window and go into my neighbors house aren't doing very much for me ;)
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Third World way to be efficient. Don't toss it if it works.
Re:Dont bother. (Score:4, Informative)
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Every cent you spend is in turn spent on power
Would someone please explain this logic to me? I mean, I understand the logic (If I pay Sally for a hummer, she might use the money to pay off her Hummer), but I just don't think it is valid. Sure, if you plot energy use vs GNP on a log-log chart (like at GapMinder [google.com], there's a relationship between CO2 emissions (a proxy for energy use, indexed for relative environmental impact) per capita and income per capita, but there's a lot of scatter and a lot of trends th
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The simplified model is still true for the price of a product. The thing that the GDP vs energy use model doesn't show is the money movement. There has always been a massive movement of money to China where they have a huge manufacturing base. Effectively when you buy that made in china toy you're sending a packet of money to china for them to spend on burning power.
The model does break down though in service industry based economies
Not one... two. (Score:4, Interesting)
If they're networked, you can just as easily copy files over when you need them, or stream media across.
Re:Not one... two. (Score:4, Funny)
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Since when do you need a fast processor to serve web pages over a (most likely) fairly slow link?
Only if IDE disks cannot fill his internet connection. I seriously doubt that is the case. And how fast disks do you need to fill IDE, anyway?
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One thing I'm toying with is finding some sort of device which can be controlled via USB or somesuch to turn on and off power at will. Thus, I could have the server
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Some info and a pic at:
http://people.debian.org/~ocsi/project/sispm [debian.org]
They were at CES last year trying to find a N.A. distributor. It doesn't look like they succeeded:
http://www.gembird.cn/index.html [gembird.cn]
I wouldn't say their stuff is particularly high quality, btw.
Re: remote power control (Score:2)
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To skimp even more, one could take a look at linux based/capable NAS and/or DSL router devices (Linksys WRT54GL or NSLU2, for example). They're cheaper and probably use even less power than an Epia, and can manage many low processing always-on tasks.
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Almost.
For fileserver/bittorrent client, use a NEW via C7 that has ONBOARD GbE and is FANLESS. The J7F4 has two GbE, is fanless, (relatively) fast and ultracheap. The EPIA EN12000 or EX10000 or Jetway J7F2+daughterboard are also good, but are more expensive. The former is CHEAP, and you can use the PCI slot for a 4-port SATA ca
Low power consumption CPU is needed (Score:2, Interesting)
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Two words. PSU & powernowd (Score:3, Interesting)
2. Run powernowd (with AMD cpus, under linux), which scales down your cpu clock if not under heavy load.
powernowd obsolete - use cpufreq ondemand (Score:4, Informative)
modprobe cpufreq_ondemand
/usr/bin/cpufreq-selector -g ondemand
now tune the up and down thresholds to your liking in the /sys/devices/system/cpu/cpu0/cpufreq/ondemand/* "files" and you're good to go.
Also, for Athlon64 and Opteron CPUs you really should enable clock divide in halt to save even more. For instructions on that read opteron-powersave.txt [electricrain.com]. (some BIOSes enable it by default, others do not)
Another mislead AMD/Intel power comparison. (Score:5, Informative)
And even when they do, it is not so spectacular when you factor in the lack of a memory controller. (I like the Core 2, hate the P4)
Sorry, this is a COMPLEX subject. How so? Intel and AMD measure Power needs by a different yardstick. AMD makes many parts, has two different processes, and even on the same process has varying power needs.
The AMD 65nm desktop chips use VERY LITTLE power, often kicking the butt of the core 2 duo, especially at idle.
If you really want to save power on a powerfull x86, you undervolt/underclock a 3600x2 65nm chip. At this point, you will worry much more about the power consumption of your Power Supply, Video Chipset and Hard Drive.
As some have suggested, Plug in a large Flash memory device for files accessed but not updated regularly, spin down the HD after a time delay(HD's have a finite number of start ups), look for an efficient supply, and look at the newer AMD integrated video chipsets.(I think you will find these chips consume much less current than others)
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I just built myself new AMD64 system yesterday, and installed ubuntu on it. It is indeed very power efficient. I'm using one of the AMD64 dual-core chips that only draws 65 W peak power. When the processors are idle, and the screen is powered down, it only draws 31 W for the whole computer! That's not in sleep mode, that's just sitting there in the GNOME desktop with the screen powe
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Is that still true? Have it ever been?
Regarding power consumtion then no, the Intel c
Don't forget the monitor (Score:5, Insightful)
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The advice is simple. Turn off all power management. If you walk away for a second your system will be ready and responsive. If you walk away for 15+min turn off your monitor. If you leave for 8hr+ turn off your PC.
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On the other hand, I want to caution that in Monitors or TV's, LCD's do not always save much power per inch of display. It depends on the model. I have one CRT that takes only 30 percent of the standby power of one of my LCD's. Since they are "off" more than on, this negates a lot savings.
An interesting side note, my CRT takes less power when displaying a primarily black
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That is expected, actually. LCD's work by blocking out the backlight. Their "natural" state is transparent, so in theory they should even use slightly more power when showing black. In practice I doubt you can measure the difference.
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Yeah, sure, brag about it.
Not sure how you got 150W, though... All common 24" LCDs have a rated max in the 95-105W range, and at least from my experience with smaller LCDs, they usually use between half and two-thirds of that rating under real-world conditions. Granted, you'll have some losses at the power supply (if it has an external brick, I don't think they need to include that in the rated consumpt
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Kuro Box (Score:4, Informative)
I just recently bought a Kuro Box for exactly the same reasons - low power, low noise, always on. You can load it up with Gentoo or Debian, so you can do bittorrent, ftp, http, etc. And it's cheap!
The only downside is that it's headless, but for me that wasn't an issue. If that really bugs you, you can set up a vnc server on it and graphically steer it from your PC.
Check out the kuro website. [kurobox.com] It has links to their wiki and forum.
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However, the power is LOW, don't expect to be able to do much other than just let it sit and serve a few bits and pieces. I bought myself a Via Epia fanless 1GHz motherboard last october, which works as a mythtv front/backend, apache server, subversion server, a synchronisat
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VIA boards work well, but not as fast as Core (Score:4, Informative)
For light-duty serving, I've been very happy with the latest round of VIA boards (and I've heard the slightly cheaper Jetway variants work just as well). I have an EPIA EN12000EG fanless board running in one of those $30 mini-tower cases from Fry's (or something). The board draws something like 13 watts at idle, and 25 under load. This includes the CPU, RAM and chipset. If you can spin down the hard drives, they'll only be a few watts more, and adding in the PSU inefficiency, it'll be maybe 40 watts AC.
If you just want to serve stuff, you can toss in a 2.5" SATA hard drive (or two, for RAID) and no optical, and fit the whole thing into a case smaller than a Mac Mini, for a lower price than the Mini, with less power consumption than a Mini, even with 2x160GB notebook drives. Or you can put in an optical drive, and it'll be slightly bigger than the Mini.
I've used one of the previous round of these as a desktop machine. Its audio is decent, and as long as you're mostly browsing the CPU is fast enough (compile jobs are slow, but they're much more tolerable with the new C7 proc). The integrated graphics suck, so you won't be gaming on it.
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For off-the-shelf desktop use, it's hard to beat the Mac Mini. Core duo, notebook hard drive, notebook optical drive, draws like 50 watts at idle.
Since the anonymous reader wants to "build" the PC, I think a Mac mini recommendation (a good pre-built choice) should be accompanied by the AOpen miniPC barebones series [aopen.com]. The specs and form factor are nearly the same, but AOpen allows a wider selection of components. Systems can be assembled-to-order at MyAOpen.com [myaopen.com]. Barebones miniPCs can be bought at many places like Buy.com and TheNerds.net.
If this form factor is restrictive, then the Mac mini's energy efficient notebook chipset (Intel 945GM) can be ha
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A laptop (Score:5, Interesting)
A laptop is already constructed to use as little power as possible, so for non-performance critical tasks, it would probably be quite useful for an always-on server. Built-in UPS is also handy, and it can be tucked away in some closet without taking any room, while still having an emergency keyboard and screen if you need to perform administration tasks on it.
For storage, a couple of USB-drives would be useful, I bet they don't draw much more power than the drive itself.
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USB drives a very bad choice for power savings (Score:2)
Same is true with most RAID adapters (Areca does support spin down).
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While it would be nice to save those three idle watts, I think the cost of a full system would probably outweigh that loss.
If using AMD Athlon 64... (Score:2)
Now, if I could make my Windows XP Pro. SP2 stable. Others and I [amd.com] can't figure out why I get blue screens with Cool'n'Quiet enabled.
Underclocking (Score:5, Informative)
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Temperatures are nice when idled (room is about 78 degrees(F):
temp1: +95 F (high = +172 F, hyst = +106 F) sensor = thermistor
temp2: +96.8 F (high = +176 F, hyst = +167 F) sensor = thermistor
A used Pentium-M based laptop (Score:5, Informative)
Get the model number of the laptop in advance, cross-reference that with the chip that it uses, then find the power consumption for that chip if you want to double check. I hear the later-model ones are (surprise surprise) more efficient, but they're all pretty good AFAIK.
As somebody else said, the built-in UPC isn't bad, and a Pentium M will have all the power you need for non-floating-point functions; any Pentium M can handle even a moderately-sized website if you wanted.
PC vs Mac electricity consumption (Score:4, Informative)
Noticing this cost, I compared a bunch of Macintosh and PCs, as you can see in this article on PC and Mac electricity use. [blogspot.com]
As you can see, it's pretty easy to see that the cheapest devices can end up costing more in power alone.
If you plan to run an electronic device close to 24x365, factor electricity consumption into your purchase decision. Also factor in devices like cable modems, wireless routers, and so-called "sleeping equipment" - in combination, they can easily put another several hundred to your electricity bill every year. I use an X10 "appliance" controller to truly switch off idle equipment.
My total monthly electric consumption these days is well under 100 KWh.
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My total monthly electric consumption these days is well under 100 KWh.
My god, what kind of house do you have to use that much electricity, and where do you live? My house doesn't use a quarter of that in a full year, including heating. And I'm in Canada!
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My god, what kind of house do you have to use that much electricity, and where do you live? My house doesn't use a quarter of that [100 KWH/month] in a full year, including heating. And I'm in Canada!
A single 100 watt incandescent light bulb, on 24 hours a day, consumes roughly 73 KWH per month:
100 watts * 730 hours/month = 73,000 watt-hours per month, or 73 Kilowatt hours per month.
Your 25 KWH over a year is equal to having a 3 watt light bulb on 24x365. Either you freeze your ass up there, or you might calculate KWH differently in Canada.
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A laptop with no fan... (Score:2)
The added advantage of these older laptops is that their CPUs do not require a fan -- the fan is the number one problem with most PCs. I've had PC's run for *years* continuously without reboots or crashes. Invariably what
Get a vhost (Score:5, Insightful)
Disk space is relatively expensive, and this may not be an option for you if by 'BitTorrent' you mean 'fill up my 500GB hard drive'.
ideas (Score:4, Informative)
As others have pointed out, if you can find an obsolete laptop, and just dedicate it for your 24/7 applications, that's going to be by far the most energy-efficient solution.
Get a Kill-A-Watt [thinkgeek.com], so you can actually measure how much power various things are using. Until I got one, I had no idea that my computer's speakers were drawing 12 W all the time, even when the computer was shut down.
2.5" hard drives are more energy efficient than 3.5" ones. You need an adapter cable, and also an adapter to mount it in a standard desktop PC's cage. A 2.5" drive is more money for the same storage, but all hard disks are ridiculously huge for most people's needs these days.
Get an 80PLUS rated power supply. The 80PLUS thing means that not only is it efficient, but it's also made in a more ecologically friendly way, without lead, etc. I've heard a lot of conflicting claims about how you should choose the capacity of your PS compared to the power your machine uses. Some people say a switching PS is most efficient if you run it near its maximum capacity, and others say it's most efficient at 50%. I came across something on usenet recently where they actually collected data, and they found there really wasn't any clear relationship. It's dangerous to get a PS that's not rated high enough, because your machine may use an unusually large amount of power during the boot process, and it may boot unreliably if your PS isn't rated high enough.
Try to get all the ACPI power management features of your machine working. Unfortunately, that can be easier said than done. Many BIOSes default to only doing S1 sleep mode, which hardly saves you any power at all. That's because a lot of older hardware can't handle S3.
For your mobo, choose something with integrated video, rather than using a video card. If you're into gaming, this is yet another good reason why you don't want your always-on machine to be the same as your main machine you use all the time.
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That's an easy way to get energy efficiency, but you can build a desktop more efficiently. 80PLUS PSU, Turion CPU, etc., and your desktop can be lower power than older notebooks, while significantly faster.
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How old of a laptop are you talking about? My svn/trac/ftp/web/email server is a 2001 IBM Thinkpad A21p (850MHz P-M, 512MB RAM, 100GB 7200rpm drive) that draws 20W idling and 34W going full tilt (with the screen off, natch). According to the numbers on the power brick, my 1999 Thinkpad 600X had similar
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I said, in no uncertain terms, "you can build a desktop more efficiently."
Slightly lower than you can from even the best laptops. Mobile components work just as well in desktops as they do in laptops (eg Turion CPU). However, you can get slightly higher efficiency from th
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I'm also talking about building a low-power computer, and in my experience, I haven't been able to get close to laptop power usage, let alone better than laptop power usage.
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Those are INSANE numbers.
A 7600 GT (you didn't specify) would almost entirely explain the power consumption.
There's a 10W difference between a MT and ML Turions.
Your PSU isn't 80plus certified, and isn't quite as efficient as you think: http://www.silentpcreview.com [silentpcreview.com]
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This [silentpcreview.com] is an article by Silent PC Review on a "Mobile on the Desktop" build up, and the best they were able to do was 22W/57W. Th
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"That's an easy way" means: that's an easy way to do okay.
That's idiotic. Just because a few people don't know how to do it, doesn't change the facts.
Be careful with VIA EPIA stuff (Score:2)
I got the "Nehemiah" version, which uses a 60mm fan. I also got a case with a fanless supply (brick + electronics in case) to try to make it as silent as possible.
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My Strategies (Score:4, Informative)
Buy a low-end video card. The high end cards are energy hogs.
Use a CPU that you can scale back operating frequency on using CPUSPEED etc when the machine is idle.
Don't buy more CPU speed than you need. Consider buying a low power version of the CPU you are getting.
Consider a motherboard that you can use a portable CPU on.
Buy the smallest feature size CPUs. They are usually more energy efficient.
Use smartd etc. to spin down your hard drives. Right now that usually means IDE drives - spinning down
SATA drives on Linux can be a challenge - it depends on kernel & drivers. Each hard drive = 10 watss
Don't install more RAM than you need.
Get a motherboard that allows you to turn off unneeded stuff like serial ports etc.
Buy an efficient power supply.
Use something like the Killawatt power meter to measure your results.
Switch to compact flourescent bulbs!!
Do all this and you should be able to get into the 60-70W idle range. Since 1W-year
=$1 that is $60/year.
The flourescents will save you at least another $100/year.
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http://forums.gentoo.org/viewtopic-t-341298-highli ght-undervolt+speedstep.html [gentoo.org]
My build (Score:4, Interesting)
MB: ASUS M2NPV-VM. AM2 socket with on-board Nvidia video, SATA etc. Not running a discrete video card is a large power savings.
CPU: Athlon 64 3500+ AM2 Lima core. This is a recent single core CPU from AMD. Easily obtainable from Newegg et al. The nice thing about it is the low TDP of 45W. This approaches portable CPUs while not costing so much. Stable at 1.2V (perhaps lower if I tried) and works well with cpufreq.
Case: Antec NSK3300 MicroATX. Small and quiet. Uses a high efficiency 300W power supply with a non-standard form factor. I doubt this machine can pull enough juice to get the fan moving at full rate. It's silent 99% of the time.
The rest: 1GB of "value ram", a pair of quiet 250GB WD disks and a Intel Gb PCI NIC I got somewhere. If you want to save more power run 1 disk, cut the RAM in half and don't add a fast NIC. Probably just under 30W at that point.
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Two boxes is the way to go (Score:3, Insightful)
If you still must have it all in one desktop machine, one way to cut the power usage if you like lots of storage is to try to only have 1 HDD in the computer, and put the rest on USB/Firewire harddrives which you can then shut off when you don't need them.
Hackable linux router (Score:3, Informative)
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Some ideas of my own (Score:4, Interesting)
Bios (Score:4, Interesting)
1) Dump the high performance GPU. A cheap PCI video card saved me 50W.
2) Seasonic makes some nice 80% efficiency PSUs. Well worth it.
3) Turn off integrated peripherals in the BIOS. Are you using the Parallel ports and serial ports? Lower the bus frequency if you can.
I found that a cron job to turn off the CPU at midnight, along with the auto-turn on timer in the BIOS set to 7:00 also worked quite nicely.
Re:24 X 7 NAS (Score:2)
I considered making a NAS, but it was about the time several NAS in a box solutions came out. Lacking space for yet another full size box and concerned about I went with one of the pre-packaged solutions. I settled on one that does run Linux. It uses a Riser filesystem. It supports both the Unix shares as well as SMB, both of which can be shut off. The drive is easly partitioned for mounting an encrypted partition. This works well. A mounted encrypted p
Silentpcreview.com (Score:4, Informative)
One word: laptop (Score:2)
I picked up an old Dell 1Ghz laptop, added an external HD with a USB enclosure, and plugged in all my gizmos with a docking station. Now it does all my 24/7 tasks, hosts my domain, etc. A PCMCIA -> SCSI card serves up my tape backup. VNC means I can keep it tucked away in my rack (though, technically, it's connected to my KVM too), it's quiet, power efficient, low heat, and a little research ensures it won't explode on me.
Don't get me wrong, it's no speed demon, things run slower than if
Not a good laptop application (Score:2, Interesting)
Think different... use an NSLU2 (Score:3, Informative)
It uses only about 5w and you can attach flash or USB disks if you need more memory.
http://www.nslu2-linux.org/ [nslu2-linux.org] will tell you everything you need to know to set up the applications you need.
Forget VIA, get an underclocked Sempron (Score:3, Interesting)
The VIA EPIA boards are all very nice, but when you look at the cost of the board, enclosure, psu etc, you realise it will take about five years to recoup the cost in saved electricity vs the Sempron.
That is the biggest problem with energy efficient tech IMHO - it's too expensive. 25 years to recoup my £10,000 investment in solar panels? No thanks.
Linksys slug - or other options (Score:2)
I use a "hacked" Linksys NSLU2 [nslu2-linux.org] to run:
I'm using it with an external USB hard-drive, but its quite possible to use a USB key (in which case it woul
Laptop (Score:3, Insightful)
Turion-based PC (Score:2)
The other option is a Mac Mini, Apple TV, or a laptop.
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USB-to-CF Adapters (Score:2)
And assuming that your OS will let you spin down the disks that aren't in use, keeping most of your running system on CF will keep things quite and low-powered except when you actually need disk.
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I had been looking into that but decided against it since I'd need a HDD anyways for all the services the OP talks about - from receiving messages, through web-serving through torrenting - you name it. By the time you're actually using your server, there's always some kind of activity that wants the hard disks spun up at least once every 20 minutes or so - so if it is effectively always spinning, then I might as well pot /boot onto it as well and skip the whole memory-stick thing entirely.
However I really
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Even better - go with an Athlon 64. In most usage scenarios (i.e. the CPU is idle most of the time) it uses even less power than the Core 2 Duo.
If you plan to run the thing at close to 100% CPU load all the time, then the Core 2 Duo is more efficient. But that's a fairly rare scenario.