Musings about a fanless PC - will this work?

[Vilx-]

For a while now I've been toying with the idea of making a totally fanless PC which will serve as a NAS/home-server. The idea is that I'd like it to be as quiet as physically possible and small too. So that I can shove it under the bed and forget that it's there.

Originally I was thinking about an Intel D945GSEJT. Seems like a perfect fit - it's a completely fanless ITX sized motherboard, with an option to have a 12V external power supply. I even got a used suitable power supply from a friend (had an opportunity to get one for nearly free).

Today however I read an article which among other things mentioned the Intel CULV series, which piqued my interest. I tried finding their prices and cooling solutions, but was unable to find anything but pre-built laptops. Along the way I also found your forum.

So... what advice from the experienced gurus? I read here that a totally fanless PC is a pipe dream anyway because it will overheat itself eventually. Is there really no hope?

[Big Pimp Daddy]

A totally fanless system is not just a pipedream, myself and many others on this forum run fanelss configs, though most newcomers are indeed scorned by some forum contributors who decry the feasibility of totally fanless.
To go totally fanless you will either need decent ventilation in the case to aid free convection, or a case that acts as a large heatsink itself, such as the mcubed types. You also need to choose components carefully.
The issue in your situation, is that a single slow rpm 120mm fan will provide enough airflow to ensure against overheating, as well as allowing more flexibility when choosing components, whilst still making less noise than any mechanical hard drive. As you are talking about a NAS, I'm assuming at least one 3.5" mechanical hard drive, this will make more noise than one or possibly two slow high-quality fans. Because of this I would recommend against fanless in this situation, but if your heart is set on it then go for it.
With regards to CPU, I don't think the Intel CULVs are available on the desktop yet, or if they ever will be due to the Atom. I would go for the Intel D945GSEJT or a similar Intel Atom board, they are very low power and you need barely any processing power to power a NAS.
Happy hunting.

[BillyBuerger]

There's also the new Mount Olive based Atoms. The CPU is basically the same thing in terms of performance and power but the important thing is the better chipset used which uses less power. Should be very easy to cool passively.

Mini-Box Atom boards

Oh right, and the SPCR review

[Vilx-]

Mmmm, the D510M0 indeed looks like a treat. And even cheaper than the D945GSEJT. However it lacks the internal power supply, which makes the whole thing more expensive again. Lots more, as the ITX power supplies that I can find are pretty expensive. Plus, I haven't seen any fanless ITX power supplies either. And what I hear about the fan-ful power supplies, they supposedly make a LOT of noise with their little fans.

As for the HDD - yes, I want a 1TB HDD there. I still don't know which one or how many rpm. I'll research this website to pick one - when I get to the point of actually trying this rig out. So far it's only an idea.

Added: Hmm... just noticed that the case I had in mind (Codegen MX-31) has a standard size PSU in it. I could then put a nice quiet 12cm standard PSU in there and that would take care of all the fan requirements, no?

[BillyBuerger]

... Plus, I haven't seen any fanless ITX power supplies either. And what I hear about the fan-ful power supplies, they supposedly make a LOT of noise with their little fans.

Well, there is the FSP120-50GNF for a fanless flex atx PSU. But yeah, having the power right on board is a nice feature and is probably more efficient. And it looks like it's hard to come by right now.

[BillyBuerger]

Opps, I really meant to mention the Sparkle SPI120GNF.

[andymcca]

Originally I was thinking about an Intel D945GSEJT. Seems like a perfect fit - it's a completely fanless ITX sized motherboard, with an option to have a 12V external power supply. I even got a used suitable power supply from a friend (had an opportunity to get one for nearly free).

I run a D945GSEJT in the M350 case totally fanless. I love it!
I am toying with drilling new holes in the HDD/Fan bracket and mounting my 1.5TB Green Series WD drive in it per this forum post, but at the moment I am making due with a usb flash boot disk (hidden in the front of the case) and a 2.5" HDD.
The hottest part is actually the northbridge, even during a CPU burn-in. I'm not sure if this would be true with the graphical output disabled. It gets hot enough that I can't keep my finger on it for more than a second or two, but not hot enough to burn me.
Without the HDD it idles at 10-11W based on my KaW.

[Vilx-]

Oh, this is just brilliant! The case costs $40, but to get it to my home (Latvia, eastern Europe) it will cost me no less than $140 in shipping!

Guess I'll have to seek some local redistributors. ebay.de seems to have something already cheaper, but still pretty expensive. Or maybe I'll have to try and get some acquaintances from the US to mail it to me. Don't know if anyone will agree though.

But nice find, I must say! The case looks perfect. If/when I get to making this, I'll be sure to buy it.

[greenfrank]

Originally I was thinking about an Intel D945GSEJT. Seems like a perfect fit - it's a completely fanless ITX sized motherboard, with an option to have a 12V external power supply. I even got a used suitable power supply from a friend (had an opportunity to get one for nearly free).

I run a D945GSEJT in the M350 case totally fanless. I love it!
I am toying with drilling new holes in the HDD/Fan bracket and mounting my 1.5TB Green Series WD drive in it per this forum post, but at the moment I am making due with a usb flash boot disk (hidden in the front of the case) and a 2.5" HDD.
The hottest part is actually the northbridge, even during a CPU burn-in. I'm not sure if this would be true with the graphical output disabled. It gets hot enough that I can't keep my finger on it for more than a second or two, but not hot enough to burn me.
Without the HDD it idles at 10-11W based on my KaW.

I have a similar rig with D945GSEJT, built just for fun and used as "spare" pc. Idles at 15w with a 2.5" hdd. Totally fanless and very quiet.
Considering all the factors (price, performance, etc.), this is still the best very-low-power pc for average use.

[andymcca]

For those who care, I monitored the temperature of the D945GSEJT in a fanless M350 setup with no HDD. Idle in Ubuntu was roughly 50C. Idle in BIOS setup was 60C (no power saving?). MPrime with 2 threads running a type 2 burn-in max out between 75C and 80C. This is all in a 25C room.

All very toasty, but according to the literature, max Tj is 90C, so these are "safe".

I did replace the factory thermal paste with some AS ceramique, but I have not seen huge changes (2-3C). It has not had time to set, though.

The N270 die is tiny! It is rectangular and between .3 and .5 the area of the 945GSE. This may explain why the heatsink feels warmer for the 945GSE, since I am probably getting much better conduction off the larger surface area. I don't have figures on the 945GSE temperatures.

Edit: There is no significant source of air currents in this room. There is a steam radiator across the room, by a window, so there might be minor convective flows, but the box was placed in the corner under a desk. This is probably as stagnant as you can expect a setup to get in an open space.

[Vilx-]

Wow, that sounds pretty hot! I didn't imagine it could be that hot just doing nothing. Still, if it's within the acceptable range, I guess it's fine. I wonder though - does it affect performance in any noticeable way?

Anyway, it's pretty clear that whatever OS I put on it (probably some Linux distro) I'll want some software that monitors the temperature and shuts down when it gets too hot.

[andymcca]

According to the N270 documentation there is "catastrophic thermal protection" which kicks in at 125C. It is a signal from the chip, so the motherboard has to handle it, but one would assume Intel read their own datasheet when designing the D945GSEJT.

The data sheets say the signal goes active at 125C, but this may not be accurate. 125C is a Tj max for some other Intel chips (if I remember correctly), so I wonder if they just copied the text from another data sheet.

In any case at temperatures under 90C I don't see anything to indicate voltage/frequency scaling to limit TDP. Is this what you meant by performance effects? As far as errors, it is stable when using the mprime burn-in.

[xan_user]

If its running that hot without a hdd, what will keep the hdd cool?

How hot are the other parts of the board that have no thermal protection?

2.6 Thermal Considerations
CAUTION
Failure to ensure appropriate airflow may result in reduced performance of both the
processor and/or voltage regulator or, in some instances, damage to the board.
All responsibility for determining the adequacy of any thermal or system design
remains solely with the reader. Intel makes no warranties or representations that
merely following the instructions presented in this document will result in a system
with adequate thermal performance.
CAUTION
Ensure that the ambient temperature does not exceed the board’s maximum operating
temperature. Failure to do so could cause components to exceed their maximum case
temperature and malfunction. For information about the maximum operating
temperature, see the environmental specifications in Section 2.9.
CAUTION
The board is designed to be passively cooled on a properly ventilated chassis. Chassis
venting locations are recommended over the processor, voltage regulator, GMCH, and
system memory areas for maximum heat dissipation effectiveness.
Ensure that proper airflow is maintained around the processor, processor voltage
regulator circuit (shown in Figure 2-10), the GMCH, and the SO-DIMM. Failure to do
so may result in damage to these components.
CAUTION
A thermal rating of 85 oC is required for the system SO-DIMM for the memory device
to tolerate passively-cooled or limited system airflow constraints.

Table 30. Thermal Considerations for Components
Component Maximum Case Temperature
Intel Atom processor N270 90 oC
Processor voltage regulator area 85 oC
Intel 82945GSE GMCH 105 oC
Memory SO-DIMM 85 oC


2.9 Environmental
Table 33 lists the environmental specifications for the board.
Table 33. Intel Desktop Board D945GSEJT Environmental Specifications
Parameter Specification
Temperature
Non-Operating -20 °C to +70 °C
Operating 0 °C to +35 °C

[Vilx-]

Is this what you meant by performance effects? As far as errors, it is stable when using the mprime burn-in.

I just remember an ancient video by Tom's Hardware. It was back in the days when the first AMD Athlons came out and they were hot as hell. In that video when the heatsink was removed from CPU's they slowed down. The Intel's just suspended (and resumed when heatsink was back in place), the AMDs burned.

I was just wondering if medium size heat would not have similar effects on todays CPUs. Like - that they would slow down.

[greenfrank]

For those who care, I monitored the temperature of the D945GSEJT in a fanless M350 setup with no HDD. Idle in Ubuntu was roughly 50C. Idle in BIOS setup was 60C (no power saving?). MPrime with 2 threads running a type 2 burn-in max out between 75C and 80C. This is all in a 25C room.

All very toasty, but according to the literature, max Tj is 90C, so these are "safe".

I did replace the factory thermal paste with some AS ceramique, but I have not seen huge changes (2-3C). It has not had time to set, though.

The N270 die is tiny! It is rectangular and between .3 and .5 the area of the 945GSE. This may explain why the heatsink feels warmer for the 945GSE, since I am probably getting much better conduction off the larger surface area. I don't have figures on the 945GSE temperatures.

Edit: There is no significant source of air currents in this room. There is a steam radiator across the room, by a window, so there might be minor convective flows, but the box was placed in the corner under a desk. This is probably as stagnant as you can expect a setup to get in an open space.

Yes, N270 temperature in M350 is around 50-60 °C (idle, after some time runnig). A good solution to reduce this temperature is to mount a slim scyte kaze fan

http://specialtech.co.uk/spshop/files/d ... u-slim.jpg

This fan fit perfectly above the cpu and is completely silent. Just turn off in bios the fan control setting, because bios would activate the fan only at high temperatures.

[andymcca]

If its running that hot without a hdd, what will keep the hdd cool?

How hot are the other parts of the board that have no thermal protection?

I actually come to the conclusion that the 3.5" drive was not doable because it would almost totally block convective cooling of the north bridge in any position I could think of. I now have a 2.5" drive installed as far from the CPU & NB as possible, and it says reasonably cool (no <30C, but I am not a disk cooling fanatic).

The north bridge is actually the hardware I worry most about, as I have no means of measuring its temperature. The memory never gets too hot to touch, and the disk drive does not over heat.

The "ambient" temperature as read by the onboard sensor does breach the 35C limit (approaches 45C in a many-hour burn in), so some of the passive components may be at risk. The entire system should be idle for the vast majority of the time, though, and should not be doing any heavy processing.

I have ordered a 40mm x 20mm fan to toy around with, since the M350 only mounts 40mm. If I can get it operating at a reasonable volume I may opt to keep it evacuating air from the case by the CPU. I'll post back about that when it arrives.

[D4Peter]

Guys, what about buying a (cheap) chassis, then drilling many holes into it at bottom, top, etc. Putting in a fanless PSU (or one part of a 2-part psu), a low-powerconsuming CPU (maybe 10W? 20W?, but quite strong (I would prefer above 1000 points is passmark (http://www.cpubenchmark.net/cpu_list.php)))
and lowpower chipset, and a huge(st) passive cpu-cooler? And, just for safety (not working at normal (95% idle) use), a 12cm fan, enclosured into the middle of an (10 cm diameter, 1m long, interwound) tube, intaking from the bottom.

(I did not succeed to hunt the concrete components yet.)

[len509]

Guys, what about buying a (cheap) chassis, then drilling many holes into it at bottom, top, etc. Putting in a fanless PSU (or one part of a 2-part psu), a low-powerconsuming CPU (maybe 10W? 20W?, but quite strong (I would prefer above 1000 points is passmark (http://www.cpubenchmark.net/cpu_list.php)))
and lowpower chipset, and a huge(st) passive cpu-cooler? And, just for safety (not working at normal (95% idle) use), a 12cm fan, enclosured into the middle of an (10 cm diameter, 1m long, interwound) tube, intaking from the bottom.

(I did not succeed to hunt the concrete components yet.)

This has been pretty much already done here.

As for drilling a bunch of holes in a case, I would just use this Cooler Master Centurion 590 case. It has a lot ventilation in the front, back, top, and sides. If you also use a Pico PSU, you can even have more air coming through from the bottom PSU space.

[andymcca]

Well after considerable testing of the 40mm x 20mm Mini Kaze Ultra, I can say that my idle + board temps hardly budged, but my load temperatures max out at ~50C.
This is with the fan mounted horizontally directly above the CPU/NB on the standard M350 mounting bracket. I have it blowing out of the case to exhaust the hot air from the heatsinks, but there is a gap and I'm not sure how much of the air it is managing to actually pull through them. I may reverse the fan to blow down on it, although I worry this may hurt my board temperature.
The fan is much more quiet than my crap 2.5" drive, but still has a definite ~15-20Hz ticking sound to it when everything else is totally silent. I sleep ~2m from it, and some nights I can hear it (when my slight tinnitus does not drown it out). The hdd is an order of magnitude louder though. I just hope the bearing does not wear out super quick because of the mounting.

Oh, and it was a PITA to install the fan. It came with long screws for NB mounting, and the holes were not standard size. I drilled them out and tapped them with some spare fan screws. The plastic was harder than most fans, so tapping them without a proper drill bit was a bit tough.