Review: VIA EPIA M w/ new Nehemiah core

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The EPIA M10000 is virtually identical to the M9000 except for the HSF and CPU. The visible changes:

  • A lower airflow, quieter fan than was found on the M9000, a detail that can be discovered only by examining the fan label.


The M10000 uses a quieter, lower airflow 40mm fan than the one used on the original M9000.
Apparently this quieter fan will be used on all the EPIA boards.

  • A slightly larger HS than the one used in the M9000.


Stacked for comparison: The M10000 (top) uses a larger HS than the M9000.

NEW HEATSINK FAN DETAILS

The Bi-Sonic BS401012M is a 40 x 10 mm 12VDC fan rated by the manufacturer for 6.5 CFM airflow at 5000 RPM and a noise level of 24.5 dBA @ 1 meter. This is some 8~9 dBA quieter than the fan on the M9000, so it is a welcome change. A quick SPL check at the anechoic chamber at UBC confirmed the reading: ~25 dBA @ 1 meter was obtained.

Subjectively, the new fan seems even quieter than the substantial -8 dBA measured difference, because the earlier fan on the M9000 has a distinctive whine while this one whines a lot less. It sounds a bit louder at 12V than our reference Panaflo 80mm L1A fan. The audible whine level is very similar! This is kind of crazy because the Panaflo is only spinning at 1900 RPM and the Arkua is at 5000 RPM. Perhaps the larger diameter of the Panaflo blades actually have higher velocity at the tips than the small 40mm fan's blade tips, and thus causes more whistling air turbulence?

Still, we do not consider the Panaflo quiet enough until undervolted by 3-4V or lower (ideally 7V or lower). The new 25 dBA BI-Sonic fan is a big improvement over the noisy AVC first used in the M9000, and quieter than 90% of current CPU cooling fans or even video card cooling fans. In our view, it's not enough for VIA to rest its laurels on. That fan probably needs to be undervolted by 2-3V for most silent PC enthusiasts to consider quiet enough. In the coolish 20C lab, undervolting the fan to 9V using a Zalman Fanmate 1 fan voltage controller made no apparent difference in stability or performance, even inside a very compact mini-ITX case (yes, we finally have one! -- more on that in another article), but it does bring the noise down to a hush.

VIA informed us that the fanless solution used in the EPIA M6000 could not be adapted to the faster CPU models. As the photo below shows, the M6000 sports a much larger aluminum heatsink. A copper version of this device might have sufficed for the M9000 and M10000.


M6000 board, with a much larger aluminum HS, does not sport a fan.

Interestingly, Mini-ITX.com reported in late February,

The long awaited EPIA M10000 has apparently reached some US online stores, but not in the form expected. The C3 powering them has the Ezra-T core as found in the EPIA M9000, not the newer Nehemiah core as initially advertised (retailers have since changed their specifications). The FSB runs at 100Mhz, and not 133Mhz - and LVDS support does not appear to be present. Cooling is improved with a double North/Southbridge heatsink and meatier CPU heatsink. It looks like VIA hit manufacturing delays with the Nehemiah and decided to quietly release a M10000 anyway, with an "M10000-II" (our name, not theirs) to follow later, with more fanfare. We'll wait for the real one...

The link above to the photos on the Japanese Akiba PC website shows the same CPU heatsink used on our sample. One assumes that the same BI-Sonic fan is used. All this suggests that VIA is juggling fast and hard to resolve both cooling and noise issues optimally. They have a reputation to maintain. After all, VIA have been pushing the quiet computing envelope for some 2 years now.



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