I'm considering a system build into some flavor of HTPC or SFF case. Primary purpose for the system will be to run Slimserver sourcing audio to the Squeezebox, low-demand file server for the home network, and to provide PVR capability. I'm considering the build versus buy path so I could be in full control of the resident software, and have the machine crunching for Rosetta during the many hours each day when it would not be performing primary tasks.

However, the machine has to be in a form factor which makes it fit into the shelves with the rest of the AV gear, and it has to be silently cooled (where silent implies not heard over the room's background noise, so I'm looking at passively cooled, heat pipe to the case, or at worst *very* quiet fan-based CPU cooler approaches).

Has anyone been down this path, digging into which CPUs consume the least power while doing reasonable Rosetta work? Casual searching has led me to reports that compare CPU power consumption while idle, but power while running a load comparable to Rosetta seems a bit tougher to get a handle on.

If someone already has a pointer to a review/report site that includes power-under-load as part of the analysis (for CPUs, or better yet mini-ITX, micro-ATX, and other similar small-form-factor systems), I'd appreciate any help. Thanks!

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I think the C2D E6300 would be a very good bet but I can't give you any figures. I think it was Tom's hardware that showed the thermal envelopes aren't really much use to go by as the lower end models are usually well below the envelope's limits.

If you get a motherboard that allows you to reduce the voltage then you will almost certainly have some room to reduce that slightly and thereby reduce the temperatures dramatically. You can always underclock if need be too, but i'd expect a C2D to be ok so long as there's suitable airflow around the passive heatsink, i.e from the PSU. The 45nm C2Ds will be out at some point too and they'll reduce the power consumption further, but I don't know when they're out.

Dual core is always useful for a server, even if just for home simply because you're less likely to get interuptions from something running at full load (excepting Rosetta or anything else on low priority).

You could even use a utility (like speedfan?) which will allow you to adjust the CPUs multiplier depending on the CPUs temperature.

Might be telling you something you already know, but I'd highly recommend you get a small PSU - don't overdo it as a PSU is more efficient the closer to it's limit it is. I'd recommend Seasonic - their 320W S12 is a great bit of kit and will be plenty for what you're after, unless you're putting in a power hungry graphics card? That way you'll use less power and create less heat, and also therefore less noise!

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If you use a middle end Core 2, and a 965G motherboard, you can use a fan less 300watts power supply and even a very quiet Thermaltake Blue Orb II heatsink.
I have a Quad core Q6600 running with this setting too, super quiet, my friends asked me if i turned off the computer in the living room. it use to be a Pentium Extreme Edition ... was loud.

Quad Core can be quiet too if you use the right devices around, and it is a lot of CPU processing power, and you ll never chalange it as personal server.

who?

You could always go with completely passive cooling. . it's not anywhere near as powerful as an Intel/AMD, but would get the job done:

http://www.via.com.tw/en/products/mainboards/motherboards.jsp?motherboard_id=450

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i'd expect you could passively cool a tualatin core p3 too, and it'll do better on rosetta than the via, while being cheaper too, but it'll run hotter than the via of course. Or pentium M would be ideal for it's v high thermal envelope (i assume core2duo is similar?) - it's architecture is a step inbetween the tualatin core and the core core i belive(!). The tualatin and pentium M are about 20-25W peak, and plenty fast enough for most uses. My 1.86GHz Pentium-M gets a RAC of over 300 if left on 24/7. I still think dual core is a good idea if you're spooling data though.

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there are many solution for passively cooling Core 2.
Especially the E series, are awesome for this.

who?

You could always go with completely passive cooling. . it's not anywhere near as powerful as an Intel/AMD, but would get the job done:

http://www.via.com.tw/en/products/mainboards/motherboards.jsp?motherboard_id=450

with a processing power close to a cellphone ... nice!!!!


just kidding ;)

who?

I have a Golden Orb II heatsink, and I can't hear it. Watercooling would be even quieter however. Core2 is a cool chip compared to P4 (and arguably AMD, but beware they're hard to compare).

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i've got a amd 64-2800+ and use it with a msi board that has core center installed on it for controlling cpu fan speed. The power supply fan is louder than the amd fan. I'm currently running at 53C or roughly 127F which is in the middle of its operating temperature range.

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Thanks for the input folks. I've been leaning towards this path: Nexus Psile 10a Black Mini-ITX Case Package, since the motherboard supports a Core 2 Duo Mobile CPU, but I haven't gone hunting for reviews yet to see if anyone has measured noise when the system is under load (read, "crunching Rosetta"). Being able to add dual tuners using the mini-PCI slots seemed pretty handy.

Then I saw one CPU review that compared the, "energy-efficient" AMD X2-3800+ and the C2D E6300, at Windows idle and with all cores running Prime95. CPU power consumption was 8W / 25W for the AMD, 26W / 53W for the E6300. Made me wonder if I should think about shifting to a Micro-ATX with the ADD model 3800+. Unfortunately, that review did not include any meroms, so I don't know (yet) where the fit in terms of power consumption while crunching.

dcdc - Thanks, I did already learn that a lightly-loaded PSU may be less efficient than with heavier load.

Ethan - I had looked at Via's C7 stuff and realized it could work for the actual mission(s) of the box, but I haven't tracked anything down yet that speaks to floating-point performance of the CPU. Are there people crunching for Rosetta with them, or does Who?s "just kidding" point actually apply?

MikeMarsUK - I'm afraid that given the location for this box, water-cooling would be a non-starter with my wife.

Thanks once again!

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Thanks for the input folks. I've been leaning towards this path: Nexus Psile 10a Black Mini-ITX Case Package, since the motherboard supports a Core 2 Duo Mobile CPU, but I haven't gone hunting for reviews yet to see if anyone has measured noise when the system is under load (read, "crunching Rosetta").

Careful! It says it supports a Core Duo (i.e. Yonah core) and not Core 2 Duo (Conroe). I'm not sure how easy Core Duo are to get hold of?

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Core Duo are also a lot hotter than Core 2 Duo?

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Core Duo are also a lot hotter than Core 2 Duo?

They are about the same, but Core 2 has more processing power, wayyyyyy more.

who?

If someone already has a pointer to a review/report site that includes power-under-load as part of the analysis (for CPUs, or better yet mini-ITX, micro-ATX, and other similar small-form-factor systems), I'd appreciate any help. Thanks!

I don't have a link, but I can offer some experience from a similar project I completed. -- I recently built a living room mediacenter desktop that sits in my stereo shelf system and gets used as a jukebox and gets plugged into the projector to play movies. It's not *too* low-profile, as the case is a bit taller than the rest of the components, but it fits right in.

http://www.newegg.com/Product/Product.asp?Item=N82E16811112082

I went with a Core 2 E6600 @ 2.4Ghz and I used the stock heatsink. I even gave it a modest bump to 2.66Ghz, and the whole system (which runs BOINC 24/7) is *still* quieter than the cable box with DVR that we got from Comcast. It's not even noticeable in my opinion. I was very happy with the result. The E6600 gives me a really nice amount of credits too. :)

HTH

P.S. I should mention that the plastic internal 3.5" drive bays they used are the only downside of the above case. Other than that, it's great.