I'm parts shopping for a new system build. Primary mission will be home file server, also platform to run Slimserver to feed the new Squeezebox.

Home floor plan and significant-other requirements mandate a HTPC-style case, on a closed-back shelf, in the A/V center within the listening room. Thus very quiet operation is a requirement (at least during hours when I'm in the room), and I have issues with getting a lot of air flow.

I'd like for the system to crunch for Rosetta if it can do so without overheating, at least while I'm not in the room (or 24x7 if I can keep the system very quiet while crunching). Operating system will be Linux, and from what I've learned so far I can see the need to undervolt using the BIOS (given fewer tools for doing this kind of thing once the OS is booted on the Linux-side).

Currently I'm adrift in a sea of confusing CPU articles, trying to make sense of power consumption numbers under load versus TDP numbers. It seems like the candidate directions would be a build using an mATX motherboard and AMD X2 3800+ ADD (if I can find one) or BE2300/2350; or use a MoDT board and a laptop C2D CPU. Numbers for power consumption under load, and details about support for undervolting seem scarce and inconsistent.

If anyone has been down this path I'd appreciate the benefit of your experience.

---

Others will chime in on the undervolting etc. But I wanted to be sure you know that you can configure BOINC (General Preferences) to run for less then 100% of the CPU time. Setting to 70 or 80% tends to make the machine run cooler at slower (quieter) fan speeds.

---

Rosetta Moderator: Mod.Sense

undervolting can make a big difference. Some of it is down to luck with some CPUs undervolting better than others.

I think the X2 3800+ would be a good choice. You're right that there is a lot of confusion out there, but there are some good articles. Here's one that recommends the Athlon X2 BE-2350 for cheap, power efficient processing. One of the main problems with comparing the A64s with the C2Ds for power consumption is that the memory controller is built into the AMD CPUs but isn't in the Intel chips yet so you need to consider total system power consumption rather than just comparing the CPUs.

You could also build a very cool running C2D system though - I bet the C2Ds can be undervolted quite a lot.

With some good thermal compound (Arctic Silver 5 or there's a new synthetic diamond one that's even better), a good heatsink, and some ducting (probably DIY) you could probably run the CPU fanless.

I would recommend a Seasonic S12 series PSU, or one of the other >90% efficiency ones from this list:
http://www.silentpcreview.com/article699-page1.html.

QuietPC have a US shop now too.

HTH
Danny

---

The AMD 64 X2 3800+ you suggest has a 90nm SOI process which means it is more susceptible to overheating than a chip using 65nm SOI's (Silicon On Insulator)
All the C2D chips use 65nm transistors and some of the higher AMD 64 X2 chips do too. Though you would have to be careful when buying to make sure you were getting a 65nm chip. As the smaller the transistors, the less heat they produce and also the less power they consume (a very important consideration when choosing a low noise system) it might be an option to wait until Intel bring out their "Penryn" line out, an extension to the C2D range, apparantly in Q3 or Q4 2007. These will use 45nm transisters using Hafnium rather than Silicon, and generate far less heat allowing for a quieter system (Intel already has a 32nm process in the pipeline and are experimenting with 22nm & 17nm!). AMD is also releasing a new line called Phenom (2 and 4 core) but I think these are still 65nm? Correct me if I'm wrong ;)
Overall it may be better just to wait a little while longer as we may be just on the brink of "easy" silent computing.

---

The AMD 64 X2 3800+ you suggest has a 90nm SOI process which means it is more susceptible to overheating than a chip using 65nm SOI's (Silicon On Insulator)

Actually it looks like the low-end 65nm AMD cpus might be quite 'leaky', meaning undervolting may not be as successful and/or heat output not so great a difference cf. 90nm (http://www.overclockers.com/tips01182/

The power output is so (relatively) low anyway on the lower-end dualcores that most decent aftermarket HSF will have no issues cooling the cpu with undervolted fans. Even passive with a well setup/ducted case (with one or two 5v fans).

on the brink of "easy" silent computing.

I think we're probably there - Mac Mini for one. And with sensible component choice (as espoused at the already quoted silentpcreview.com) it is quite easy to set up near silent computing (HDDs being the primary difficulty, rather than CPU cooling).

It seems like the candidate directions would be a build using an mATX motherboard

Keep in mind that most mATX boards don't have great BIOS options; you may have more undervolting success with a full ATX, but just research the model you're going to buy first really.

---

Crunching Rosetta as a member of the Whirlpool BOINC Teams

or just by a real laptop ;-)
not these desktop replacement things...

---

Team mauisun.org

a laptop motherboard (or a desktop board for a laptop cpu) with a Pentium-M would be a great choice, but you'll probably pay a bit more for it.

---

Or a LOT more!

Unless you really, really, need the 10W fewer, I don't think it's worth the price premium with the plethora of low power desktop CPUs available now.

However, it's ultimately up to each purchaser!

---

Crunching Rosetta as a member of the Whirlpool BOINC Teams

Or a LOT more!

Unless you really, really, need the 10W fewer, I don't think it's worth the price premium with the plethora of low power desktop CPUs available now.

However, it's ultimately up to each purchaser!

I was looking on ebay and the Celeron-M's are amazingly cheap - the 1.6GHz ones go for around £8 inc P&P and they're decent crunchers)! They're one of two Celerons that are much better than the Celeron tag would lead you to believe (with the other being the P3 Tualatin Celerons) - they're Pentium-Ms with 1MB cache instead of 2MB and without the lowest sleep state which makes no difference if it's crunching anyway!

The only problem is finding a cheap motherboard for them. If I can find a laptop board with a decent graphics card, or a cheap desktop board then I'm going to get it. I'm not sure how to get the OS up and running when using an external monitor - it might not sure if they output post options etc to the external monitor?

---

celeron! ewwwww

Or a LOT more!

Unless you really, really, need the 10W fewer, I don't think it's worth the price premium with the plethora of low power desktop CPUs available now.

However, it's ultimately up to each purchaser!

I was looking on ebay and the Celeron-M's are amazingly cheap - the 1.6GHz ones go for around £8 inc P&P and they're decent crunchers)! They're one of two Celerons that are much better than the Celeron tag would lead you to believe (with the other being the P3 Tualatin Celerons) - they're Pentium-Ms with 1MB cache instead of 2MB and without the lowest sleep state which makes no difference if it's crunching anyway!

The only problem is finding a cheap motherboard for them. If I can find a laptop board with a decent graphics card, or a cheap desktop board then I'm going to get it. I'm not sure how to get the OS up and running when using an external monitor - it might not sure if they output post options etc to the external monitor?

---

celeron! ewwwww

I'd expect a 1.8 Celeron to get a RAC of around 240! You can always scrape off the celeron print!

---

celeron! ewwwww

I'd expect a 1.8 Celeron to get a RAC of around 240! You can always scrape off the celeron print!

lol,scrape off the paint, thats a good one.

---

dcdc,

the Pentium-M 1.6 is a 1MB cache (in my bunch of computers). teh 2MB versions didn't come to a little later.

Though don't believe the RAC/credit of it atthe moment as Ubuntu has a tendency to drop it down to 600MHz while its crunching. I need to force it to Constant or Performance mode rather than On-Demand mode for it to stay at 1.6GHz.

But you can pic up damaged (LCD damage normaly) laptops for not so much these days. External is fine, some have option to boot Dual LCD/VGA in the BIOS so that should be ok, also FN+F5 or similar on the keyboard switches between them.
For Media Centre PC's you don't need that powerful a graphics card.
My GeFocrceFX copes no problam so should all the IGP' by intel / ATI etc..

My older M6 (Radeon) also outputs to the screen perfectly fine, though you don't get the hardware accel. stuff.

Gaming, well you'll need to spend quite a bit more to get the laptops with them in them and then they are usually desktop replacments :-(

---

Team mauisun.org

looks like you can get either 512KB or 1MB Celerons - http://www.intel.com/products/processor_number/chart/celeron_m.htm

There's 1.4GHz/1MB Cel-Ms going for around £6 incl P&P - if i was building a cruncher/server on a budget i'd be going for one of those or an S939 and a venice 3200+ E6 stepping.

---

and here are some similar in stats AMD processors:
http://www.amdcompare.com/us-en/desktop/Default.aspx

---

http://www.computeractive.co.uk/vnunet/news/2195087/amd-takes-aim-low-power

---

Sorry...linky to that.

---

I have a 4400 X2 running at 1.35v with an after market cooler and my own pwm circuit for fan control. Working very well under load its only 42C (Core temperature monitoring software)
HERE
and very quiet.
I was running at 1.45 with over clock and thought about dropping the core volts to reduce temperatures.


CPU-Z HERE claims 2420Mhz @ 1.35v, I have not tried more but it is stable at this. I can knock off one of the cores and run Oblivion on the other. Crunching and playing...

Wife: Are you playing on that thing again?
Me: Sorry love, just trying to find a cure for major human diseases, wont happen again.

Hope this is of use

---

Click below to see my werewolf