In the past months I presented you 3 boards from Technobit and today I'm happy to give you my opinion about the latest build from the Bulgarian Company - HEX8A1.
The miner in focus today is based on Bitmine Coincraft A1 28nm chip delivering more than 30GH. So far this is the first 28nm chip available for DIY projects and third party designs, and as it seems the board from Tehnobit is the first in production and shipping.
There are several differences in the design from the past generation of HEX boars, the first thing you will notice is the size of the cooler - it's huge compared to older versions. The board itself is equipped with 8 Coincraft chips, squeezed between two heatsinks and two 92mm fans. Also the molex connectors are replaced with two 6-pin PCI-Express connectors. All of these changes are due to more powerful chips requiring better power modules and cooling.
HEX16B (BitFury) and the new HEX8A1 boards side by sidePerformance:At the Technobit's
site, HEX8A1 is advertised as 260GH miner in turbo mode, so let's see how it handles various settings.
![](https://ip.bitcointalk.org/?u=http%3A%2F%2Fi.imgbox.com%2Fr5iYqwzt&t=665&c=5AzAYHuDZ9VUyw)
Indeed with moderate overclock the board is hashing with 260GH/s, but the first thing you will notice when this beast is powered on is the noise, we'll get to that later. Let's focus on performance and power consumption. According to Bitmine's pre-production specifications, the chip can deliver 40GH in Turbo mode with power usage of 1W/GH as you can see from chart bellow that is not the case.
![](https://ip.bitcointalk.org/?u=http%3A%2F%2Fi.imgbox.com%2FtFupZKN2&t=665&c=rmffnw8G1oYlpg)
The power supply used for the test is
FSP600 50ARN 88+, it is rated to "reach up to 88% efficiency" that's what the second power column is representing Wall power consumption minus 12%, the efficiency of the board is calculated with these numbers. I tried an CoolerMaster B600 (85%) for comparison but it draws around 32W more power at 260/1000.
At lower settings 230/860 the efficiency is 1.09 W/GH and if you take out the cooling it gets around 1 W/GH for the board itself, of course if we go at lower settings let's say 200/860 we'll achieve even greater efficiency but IMO it's not worth it at least not now, maybe in a year time...
About the voltage I tried 850 and lower settings but it wont's hash or unstable. It is also important to mention that the real chip freq is multiplied by 4 so when you say 250 it's really 1000Mhz core chip frequency.
![](https://ip.bitcointalk.org/?u=http%3A%2F%2Ft.imgbox.com%2FlQiiDngQ.jpg&t=665&c=-1oX6g80AlGDcg)
Each chip has 32 Engines, you can have 1 or 2 faulty per chip but thats not a problem. If you try to "undervolt" more keep an eye on the Engines if there is not enough juice you will get lower engines which is a good indicator, although with lower voltage and one or two chips with 28 engines I get some strange (better) results in efficiency perspective. it's all about finding the right ratio for your device - freq/voltage. I recommend 960/1000 it's very stable and you will get results from 255 to 265 GH/s depending on your chips.
Cooling:This thing is LOUD !!! No seriously, it's pretty much a vacuum cleaner. Despite the huge sink the board needs powerful fans to cool down the 8 chips in a small area. According to Technobit the chips need to be close for the chain to work properly so no way around it.
The smaller fan is known from the latest versions of HEX16A2 and HEX16B:
Sunon PF92251V1-000U-A99 Dimensions: 92x92x25 mm
Power: 4.7W
Speed: 4500 rpm
Air Flow: 75 CFM
The big fan is:
Sunon PMD1209PMB1-A.(2).GNDimensions: 92x92x38 mm
Power: 12.5W
Speed: 4900 rpm
Air Flow: 120 CFM
Both fans are very dangerous and there are some reports for injured fingers from the previous boards. I'm happy to see that Technobit have taken precautions with the fan grills. The noise is about 60dB at 15cm and 55dB at 1m i.e. LOUD
![Smiley](https://bitcointalk.org/Smileys/default/smiley.gif)
At 260/1000 the sink temperature close to the chips is 46C at 26C room temperature, with the help of a fan regulator I lowered the fan a little bit and the temperature raised to 50C but noise was significantly lower.
If you are planning to mine at home I recommend to get the new 4 chip version of the board for half the price. It will be equipped with 2 x 2W Sunons and probably much quieter solution.
Note: According to Coincraft A1 specification about 70% of the power is being dissipated through the ground pad and about 30% through the top of the package.
Pricing:Note: Updated Price ChartWith the latest GOX FUD the bitcoin price is going down, however I believe that Gox will "fix" their withdraw problem "soon"
![Smiley](https://bitcointalk.org/Smileys/default/smiley.gif)
As always investment in bitcoin equipment is risky but let's see what can you order/buy from various mining manufactures. Technobit are selling HEX8A1 for 999 Euros full price which seems normal to me.
![](https://ip.bitcointalk.org/?u=http%3A%2F%2Fi.imgbox.com%2FDyWarFTY.jpg&t=665&c=jYEtGIXmBdYrkQ)
As you can see from the chart the main competitor to HEX8A1 is Bitmain's AntMiner, especially if you live in a country where Customs are not a problem for the rest of us importing an Chinese miner can be a hassle. On the other hand Bitmine are selling fully equipped miner with PSU and everything you need. Even more interesting is the newcomer - The UK based company BitcoinUltra, they have good price and ETA, but no working prototype. I assume they will be using A1 chips too but that's only a guess. The race is on and much more to come from BitFury and ASICMINER with their crazy low price per GH, even BFL can ship something soon - doubt it
Software:Technobit's HEX line still lags proper mining software for Windows where you can only mine with their special
HEXMiner, the driver is in the inf folder. The setup is similar to HEX16A so you can check nemercry's
video tutorial for Windows.
As with the previous HEX board I highly recommend that you get one cheap TP-Link TL-MR3020 and
flash it with the firmware from Technobit's website. You can also order it directly from them at slightly higher price, but pre-flashed and ready to rock. In the end you are paying a thousand euros for the miner, so 30 more for the router is nothing. Of course if you have a linux host it will best to just compile cgminer with the latest patch from Technobit or download my build for Ubuntu x64
cgminer4_0.2.2Here is how to compile
git clone https://github.com/ckolivas/cgminer.git
cd cgminer
wget https://dl.dropboxusercontent.com/u/8082585/cg/2786526d9f1acb7bd903ece3c822c2c9203aa0b7.patch
git checkout 2786526d9f1acb7bd903ece3c822c2c9203aa0b7
patch -p1 < 2786526d9f1acb7bd903ece3c822c2c9203aa0b7.patch
./autogen.sh --enable-hexminer8
make
I start cgminer with the following line:
sudo ./cgminer -c ./cgminer.conf --hexminer8-set-diff-to-one 0 --hexminer8-chip-mask 255 --hexminer8-voltage 1000 --hexminer8-options 8:260
where cgminer.conf is in the same folder and with your regular settings.
Pros:- EU Based
- Efficiency - 28nm
- Availability
- Software voltage control
Cons:- Noise
- Loud
- No thermal sensor
- as usual no cgminer/bfgminer for Windows
Conclusion:Yet another good product from Tehnobit, even that the noise is a huge drawback for most of the miners. The efficiency of the board is good, not as good as promised by the manufacturer but still better than most of the miners on the market. In the end the Bulgaria based company once again did a great job with this challenge and what surprises me the most is that Technobit are shipping before Bitmine.ch
Full gallery can be found here:
http://imgbox.com/g/eKqOvbI9Uvbest
2GOOD