Came across this when I was browsing for a Mini-ITX board for the in-laws MCE, and it seemed too interesting to pass by - only one in stock

Information on this board seems pretty scarce, Asus's website doesn't even have a product page for the HDMI-equipped variant yet. Only difference seems to be the HDMI port though, so this link should provide some details: http://www.asus.com/Motherboards/Intel_CPU_on_Board/C8HM70I/

The essentials:
Intel HM70 chipset
Intel Celeron 847 ULV CPU, dual-core
Dual SODIMM slots, max 16GB RAM, DDR3-1066
PCI-e x16 slot
1 SATA 3Gb/s port, 1 SATA 6Gb/s port
2 x USB 3.0 ports on back panel

The board was not too expensive, paid around 80 euros for it. Currently I am just using it for testing / playing around, but it will probably end up on a family members desktop at some point. Test system currently consists of:

Asus C8HM70-I/HDMI motherboard
1 x 4GB Kingston SODIMM DDR3-1066 module
OCZ Vertex2 60GB SSD
bequiet PurePower L7 350W PSU

The CPU is cooled by a heatsink attached with pushpins, and a 40mm fan on top. The stock fan runs @ 4300rpm (apx) and sounds quite 'buzzy'. The motherboard has a 3-pin header for the CPU fan (monitoring only, no "smart" BIOS controls for fan voltage), and a 4-pin PWM header for a system or case fan - this does support Asus' 'Q-Fan' control system though.

With the stock fan, the CPU temperature reading just sitting in the BIOS is apx. 30C. This is on an open testbench (Lian Li T60), 22C ambient. I replaced the stock CPU fan with a Scythe Mini Kaze 40mm, 10mm height fan - at 12V this does apx. 3500rpm. This is a lot quieter, and does not exhibit the same buzz as the stock fan. I have since put a 9V resistor on the Scythe, which helps even more.

Will update this thread with some more details when I have time to test some more ... Am planning to test Netflix HD streaming in Windows 8, Blu-Ray playback with Arcsoft TMT5 and maybe a little stress testing of the CPU (Prime95 or similar). Will measure power draw as well.

Regards,
Gramkow

Very interested to know the power draw on this, please let us know when you have a chance

Tested it briefly over the weekend - the PSU I am using currently is only 80 Plus certified, so efficiency at really low loads isn't too good, so I won't go by those numbers.

I have an Akasa Crypto case with external 60W PSU arriving later this week - will test again when I get it fitted into that.

However, temperature measurements (using Asus' own Probe utility) look pretty decent. On the open testbench, running 100% CPU load with Prime95 (one thread for each CPU core) and running Blu-ray playback over the network at the same, CPU temp stabilized at 45C - up from 35-36C when idling on the Win8 desktop... Bodes well for decent operating temps when fitted into a case.

/ Gramkow

I would definitely move to a passive CPU cooler on this and then have a zero moving part PC. Maybe there is no off the shelf passive cooler but with a little modification I'm sure many CPU coolers could be made to fit the bolt pattern for this motherboard.

UPDATE

Got the motherboard and SSD fitted into the Akasa Crypto case today. Replaced the Akasa 50mm system fan with a Scythe Mini Kaze (SY501012M) and put a resistor cable on it - 9 or 7V, haven't measured. It is inaudible at that voltage but still moves a decent amount of air - certainly significantly more that the last Crypto build I did, where I used a 50mm NoiseBlocker fan.

So, power draw and temps. This is the 60W version of the Crypto, which has a smallish 60W power brick - it is quite a bit smaller than the 80W version they also sell.

All measurements taken using a pretty high-quality 'Made in Germany' power meter

Config:

Akasa Crypto Mini-ITX case with 60W external power brick
Asus C8HM70-I/HDMI motherboard
Kingston SODIMM 1 x 4GB, DDR3-1066
OCZ Vertex 2 60GB SSD

Idle Windows 8 desktop after disk activity settles down: 19-20 watts, CPU temp 39-40C
Prime95 with both cores loaded @100%, after 45 minutes: 30 watts, CPU temp 50C
Netflix HD playback using Win8 App, 21-22 watts, CPU temp 40-42C
TMT5 Blu-Ray playback, 25-26W, CPU temp 42C

All in all, really impressed with this cheap little build. I did try disconnecting the CPU fan and running Prime95 - temps rose quick to around 60C, and slowly from there up to 73C after apx. 10 minutes, when I stopped the test. So, fanless may not be the best option unless you replace the heatsink with something a bit beefier - or provide better airflow around the heatsink than what the Crypto offers.

Regards,
Gramkow

Thanks very much for coming back with those figures!

Personally a massive disappointment, double the wattage of the Intel NUC and right on a DQ77 board with an i3 etc (Huge price difference aside)

I was hoping these would be 10-15w, I've wasted a lot of money on fancy mobile itx boards and processors and unfortunately there seems to be a common theme, unless it is made by Intel efficiency sucks

Well, personally I am quite happy with the power draw figures, especially considering the cost of the system as it stands now:

Motherboard with CPU €80
SODIMM 4GB stick €20
60GB SSD €40 on sale
Akasa Crypto case 60W €80 including the Scythe 50mm fan

Total system cost was apx. €220 including shipping costs.

Efficiency would probably be a little better with a PicoPSU and class V brick, but I do not have any handy to test with, and it would be €80 spent on a possible 3-4W reduction in power draw.

The NUC itself costs around €300 in these parts, not including storage or memory - even going cheap on both, you're looking at a total cost of apx. €360

If we generalize a bit and say that a NUC would draw on average 10W less both for idle and load scenarios, then the extra power usage per year would look like this:
10W x 24 hours x 365 days / 1000 = 87,6 kilowatts per year
One kilowatt costs apx. €0,29 where I live, meaning the extra power draw would increase my energy bill by 87,6 * 0,29 = apx. €25 per year if the system is running 24/7.
Thus, the extra €140 for the NUC would take at least 5 years of continuous use to recoup on the power bill (all things being equal)...

I know that I am painting in broad strokes here, but the cost of the hardware needs to be factored in when discussing power efficiency and the total cost of ownership.

Regards,
Lars

Well, that's one way to see it. You could also say that by spending just a little bit more than that €220 you could have a beefier system (H61+G550 or something) and much the same power draw.

It's a fair argument. However the current configuration suits the intended purpose just fine for now

Mighty tempted to get a PicoPSU to test with though ... Vicotnik, you have a few of these and live in Scandinavia as well - where do you source yours (including power bricks) ?

Regards,
Gramkow

Got hold of a PicoPSU 90 and tried that with the C8HM70-I/HDMI board, to see if the Akasa DC-DC board was to blame for the poor efficiency.

It isn't.

Compared to the DC-DC board in the Akasa, the PicoPSU cut less than one watt off the idle power usage. Both tested with a class V AC adapter.

Regards,
Gramkow

Is there any way to reduce the power consumption by changing settings in the bios while keeping the ability to playback hd content? (e.g. underclock)