Scythe's e-Otonashi fanless EPIA-M cooling case

Cases|Damping | Cooling
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PERFORMANCE & NOISE

Rather go through the details of the VIA EPIA M10000, I refer you to the linked review of the integrated board. It is a fine PC for the great majority of PC users who are non-gamers, with plenty enough power for office-type apps, web-browsing, email, etc.

Windows XP Pro SP1 installation went fine with the external USB optical drive, although as with other M-ITX setups I have done, installation of the enormous number of XP updates and fixes can be excruciatingly slow. I believe this has something to do with the system scanning most of these updates do as they're being loaded. There is something the VIA boards don't like about Microsoft's procedure. After it was all done, I spent a few days using the system off and on to get a good feel of it before starting to measure, analyze and write.

Cooling

The following tools were used to test the thermal performance of the system. Links to all of this software can be found in SPCR's Software section of Useful Web Links:

  • CPUBurn processor stress testing utility
  • DTemp hard drive monitoring
  • Motherboard Monitor 5 motherboard monitoring utility

One other testing device is a Kill-a-Watt AC power meter. The ambient temperature during testing was 22°C.

Activity
CPU
System
Hard Drive
AC Power
Idle
33°C
29°C
40°C
23W
CPUBurn
72°C
34°C
41°C
40W
CPUBurn2*
72°C
36°C
38°C
40W

*Case turned on its side, for vertical orientation, HDD on bottom.

The only temperature that's a bit high is the CPU; as mentioned in the past VIA CPUs have a reputation for excellent toughness and performance at high temps, and 72°C is nowhere close to a danger zone for the VIA CPU. Both System and HDD temps are very modest, probably due to the generous ventilation that the case features on five panels.

It's interesting that the CPU temp remains completely unaffected when the case is turned on its side, which tends to substantiate TS Heatronics' claim about their heatpipe not being affect by gravity. My guess about the System temp rising is that the sensor for this is "downwind" of the CPU HS when the case is turned on its right side. In other words, the heat from the CPU is rising up to that sensor, and causing the System temp to register higher. A similar effect is happening with the hard drive: The heat from the internal PSU circuit no longer comes straight up from below it, but rises towards the CPU and motherboard area in this vertical setup.

Here's a comparison against the similarly outfitted prebuilt Mappit A4F PC:

System
CPU
System
Hard Drive
AC Power
Mappit A4F
70°C
41°C
53°C
41W
e-Otonashi
72°C
34°C
41°C
40W

The CPU temps are close enough that variances in CPU samples and assembly could reverse the numbers, so I'd consider the CPU cooling of the two systems equal in performance. The differences in System and HDD temps are easily explained: The e-Otonashi's cover is very openly ventilated while the Mappit is completely enclosed.

Noise Analysis

The parts in my sample of the e-Otonashi don't make ANY noise. The PSU circuitry is dead silent, and if the power brick makes any hum, it is too low to be noticed. There are no fans, no hum, no tinkling of water -- no noise at all from either the cooling system or the PSU.

The point is here simple: Whatever noise comes from a Scythe e-Otonashi system will depend entirely on your choice of drives. Choose a quieter drive and you will have lower noise.

The noise level of the system with the Seagate Momentus hard drive was very low, but marred by the drive's high frequency whine, which is clearly audible from several feet away in a quiet room. Missing is the lower frequency hum that emanates from any PC with a 3.5" hard drive mounted normally to the chassis. The vibration level of this notebook drive is minuscule in comparison to any 3.5" drive, so the difference in vibration-induced chassis noise is dramatic. Most of this noise occurs in the low frequency area around 100~120 Hz.

The Seagate Momentus is not in the same noise class as the amazingly quiet Fujitsu notebook drive in the Mappit A4F: It has quite a bit of high pitched whine, and its idle whirring is higher than that of the Fujitsu. It also seems to go through fairly frequent heat-resetting types of noises, a bit like the Hitachi/IBMs, but much softer.

Naturally I had to try using the whisper quiet Fujitsu MHT2040AT 40G 4200 RPM single-platter drive (from the Mappit A4F) in the Scythe / Heatlane e-Otonashi.

The result was noise performance maybe 2 dBA louder than the vanishingly quiet Mappit. The very quiet Fujitsu drive does not change its noise output, but the open vents all over the case of the e-Otonashi allows much more of the acoustic noise to get out of the case. The all-closed Mappit blocks more of the acoustic noise from getting out.

Rough Noise Measurements

I decided to try and measure the sound pressure levels. The testing was done in the lab, an acoustically reflective converted kitchen, at around midnight when ambient noise is low.

The actual SPL reading in the room with all noise producing equipment turned off was ~16 dBA, which unfortunately is still too high for really accurate measurements of these systems. The SPL readings of the gear were only marginally above the ambient level, so their accuracy is definitely not assured. Good acoustic practice requires that the ambient noise level be at least 6 dBA below the SPL of the noise source being measured.

  • Turning on the e-Otonashi system with the Seagate Momentus drive raised the noise level to 21~22 dBA at 1 meter distance from the unit. It is very quiet except for the high frequency whine, which is annoyingly, easily audible.
  • Turning on the e-Otonashi system with the Fujitsu drive raised the noise level about 2~2.5 dBA, to 18~18.5 dBA at 1 meter distance from the unit. It is audible but extremely quiet.
  • Turning the Mappit A4F on (w/ Fujitsu drive) raised the noise level just 1 dBA, to ~17 dBA at 1 meter distance from the unit. The overall noise signature is similar to the e-Otonashi; it is the same drive being measured. But overall, the sound is quieter still, more subdued and muffled.

Obviously, there is a tradeoff between heat and noise in any system. In the e-Otonashi, the case seems geared more for good cooling of added drive components than the lowest noise. According to Scythe, this is because in Japan, their first market, ambient temperatures can reach 35°C or higher in the summer. They wanted to ensure that the system would be able to stay cool even under such conditions.

NOTE: The manual has a comment about recycling the 40mm fan from the original EPIA CPU heatsink: There is a place for a 40mm fan on the back panel just behind the PSU circuit board. The fan from the original heatsink can be installed here for additional cooling if necessary.

CONCLUSIONS

The Scythe e-Otonashi integrated fanless CPU cooling case and PSU for VIA EPIA-M Mini ITX boards works exactly as claimed. It is completely silent: It cools the EPIA M10000 CPU well enough, and its power supply works noiselessly. Whatever noise from a system built around this product will come from the other components you choose to put in it -- namely the drives.

This product shares with previously reviewed Scythe products a kind of fussiness, along with a quirky and inventive design sense, which is ultimately effective. Some assembly details might be improved. There is, for example, a question of how tight is tight enough for the two screws that sandwich the CPU between the original heatsink, the heatpipe and bottom heatsink. And the top front edge of the cover does not align right up against the back edge of the front panel, leaving a tiny gap that seems a bit glaring. The fit with the VIA board is precise, however, which is nice to see.

Given the somewhat fussy procedure for assembly and the loss of motherboard warranty that CPU heatsink removal probably entails, this product might well end up being sold in a prebuilt system and warrantied by some retailers or system integrators. This assumes that the product is more widely distributed than it is today.

The asking price of US$198 seems well justified, especially given the absence of any alternatives to an integrated noiseless case, cooler and PSU combination for the EPIA M boards. Just finding or creating a CPU heatsink that will cool EPIA M10000 CPU silently is a challenge; as far as we know, no one has offered an aftermarket heatsink replacement for this part (which uses a fan that's too noisy for PC silencers.)

Pros
* Makes no noise at all
* Fanless CPU cooling
* Fanless universal voltage power supply
* Compact, efficient design
* Good workmanship, fit and finish
* Assembly is not that difficult
* Fair price
Cons
* Doesn't block HDD noise
* No front panel ports
* Only fits VIA EPIA M boards
* Uses more expensive notebook drives
* Instruction manual is a bit skimpy
* Assembly is not that easy

The e-Otonashi is definitely not a product for everyone. It is essentially an enthusiast's case, for someone who is:

  • satisfied with the performance of EPIA M6000 or M10000 integrated motherboards -- actually this probably covers 80% of non-gaming PC users.
  • handy and willing to assemble a system on their own as a kit, with some modding-type tasks that will void the motherboard warranty (though most people have friends who are technical and handy and willing to help with a project like this)
  • looking for a compact, minimalist PC that functions without extras -- or noise

For its target market, Scythe have scored a bull's eye with the e-Otonashi. Highly recommended -- for the right buyer or user.

Our thanks to Scythe for the e-Otonashi sample and their kind support.

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