Archive for the ‘Mining Hardware’ Category

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Time for a bit more in-depth look at the operating temperatures of the iBeLink DM384M X11 ASIC with the help of a thermal imaging camera. We are starting with the front and rear of the case that the mining ASIC uses, the front has four powerful Delta Electronics server fans that such cold air through the whole case where the mining blades are and the hot air exits directly through the back of the case. There are no other fans at the back, just open space for the hot air to exit the case of the device effectively cooling. The only other fan is the one of the server grade power supply that is mounted inside the case, another server grade Delta Electronics fan that is also powerful and noisy when in operation. The fans do not have power control, so they operate at maximum RPM all of the time making the device quite noisy, but also effectively cooled even in no so cool environment.

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The four blades with ASIC chips are located on the side of the cooling fans and on the other side of the case is the power supply with the Raspberry Pi controller mounted over it. The side with the RPi and the power supply is pretty cold compared to the side where the four blade with 48 chips each are located. As one might expect the hottest part inside the miner are the ASIC chips, the rest remains pretty cold thanks to the high airflow provided by the cooling fans. Even the heatsink that are on the back of the PCB with the chips remain pretty cool thanks to the high airflow passing through them.

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And now let us take a look at the chips themselves as the hottest element of the iBeLink DM384M X11 ASIC miners. Under the stock operating conditions they do remain with a surface temperature range of about 60-68 degrees Celsius as the temperature varies slightly depending on their position on the blade. As we’ve said already the cooling heatsink is not placed on top of the chips themselves, but instead is on the back of the PCB. This is the easier way to make things work, but not the most efficient for cooling as the chips use the PCB as a large heatspreader that then passes the heat to the large heatsink. This results in higher operating temperatures of the ASIC chips as there is no direct contact, but the temperatures are still Ok for normal operation. You should however be careful should you decide to overclock in order to get some extra hashrate as this will increase the operating temperatures of the chips. It seems that iBeLink has already chosen the optimal operating frequency for the device that results in very little HW errors while providing optimum performance. Further increasing the PLL frequency over the stock 110 MHz even with just a few Megahertz may result in increased percentage of HW errors.

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Normally when you run a multi-gpu mining rig you are monitoring the operating temperature of the GPU and if it is keeping an acceptable level, then you think that everything is fine and may not pay attention to other components. We have done an interesting experiment with a Gigabyte GeForce GTX 970 WF3OC-based mining rig taking thermal images of the back of one of the cards in the setup while it is mining Ethereum and while it is mining Decred. As you probably know the Dagger-Hashimoto algorithm used by Ethereum is heavier on the memory even though the total power usage is lower while Decred and the Blake-256 implementation it relies on is more power hungry and not so dependent on the memory.

The power usage of the GTX 970 while mining Ethereum is around 150 Watts while mining Decred it goes to about 175 Watts. The GPU temperature of the GTX 970 while mining Ethereum in the test mining rig is around 68 degrees Celsius while mining Decred it goes to about 75 degrees Celsius. This of course is with custom settings for the fans, because normally Nvidia wants to keep the target temperature at 80 degrees Celsius, but that might not be that great for 24/7 mining. But if you look at the back of the GPU with the help of a thermal camera you can find pretty interesting things like the fact that the backside memory chips that do not have cooling like the ones on the front of the card actually get pretty hot. A bit too hot if you ask us especially in the case with Ethereum mining with their temperature reaching about 105 degrees Celsius while the back of the card itself remains at not more than 75-80 degrees. In the case of Decred mining, even though the total power usage is higher, the memory chips remain with over 20 degrees lower temperature and the back of the card is similar in temperature, so the difference of the overall temperature is not that big.

So if you are mining Ethereum, especially if you are getting into it just now, you might want to be sure that the GPUs you are using have better cooling on all of their memory chips, including the ones on the back of the card if there are such. While there might be no issues in short term with such higher operating temperatures of the video memory chips, on the long run temperatures of over 100 degrees Celsius might cause you hardware issues and you would want to avoid these on a mining rig that needs to fun 24/7. Do note that while this experiment was performed on Nvidia-based hardware you can expect to see similar results on AMD-based video cards as well with Ethereum driving the temperatures of the video memory higher than other mining algorithms.

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Looking at the official specifications of the iBeLink DM384M X11 ASIC miner state that the device should be capable of 384 MHS X11 hashrate (plus/minus 10 percent) with a power consumption of 715W measured at the wall with 25 degrees Celsius ambient temperature. This should be the numbers for the default configuration, however we did some measurements ourselves in order to get more accurate results in order to be able to do better calculations about the cost of operating the device. We have already measured on NiceHash an average hashrate that is slughtly above the official number of 384 MHS, so this is good, but what about the actual power usage and more importantly noise level. In our first impressions from the device we already mentioned that it is pretty noisy and not suitable for use in room where people will be present, but let us see what is the exact noise level as well.

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The power supply built into the miner is an 850 Watts server grade one that is compatible with 100-240V range (for worldwide use). The exact model is ASPOWER U2A-A20850-D and according to the official specifications is it rated as 80 Plus Silver, so a high efficiency solution. At stock settings (110 MHz PLL) the power usage we have measured on the wall with 230V EU power input was 686 Watts as you can see on the photo, the power usage in Watts might be slightly higher in US and other 110-120V countries due to slightly lower power efficiency. Increasing the operating frequency with +1 MHz steps is resulting in the power usage going up with about 5-6W on each step, so the 850W capacity of the PSU should be able to take up some nice extra overclock if the chips are capable of working well when overclocked and cooled well. We are going to be doing more extensive testing about the overclocking potential with results on the power usage and performance changes, working temperatures and cooling very soon.

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Now for the noise level, as already mentioned it is pretty high… just like from a rackmountable server for example. With a measurement showing about 72.6 dBA average it is perfect to be installed in a data center or a dedicated mining room, but it is not suitable for home miners as the noise level is too much for people to be in the same room for more than a few minutes… and even in the next room it might be quite noisy. The reason for the high level of noise is that the unit uses server grade fans by Delta Electronics and they are set to run at maximum RPM all the time (no temperature control). The same goes for the fan used in the power supply, a powerful Delta Electronics fan running at maximum RPM all the time, even though the PSU is highly efficient and there is not so much heat generated. The good thing about this default fans setup is that even at not that good conditions such as high ambient temperature the miner should be able to operate without any issues at optimum level. The not so good part is that small miners might have issues with the high level of noise and would probably want to do something to make it less noisy without compromising performance – this is possible with some modifications and we are already working on a solution to optimize the cooling, so more on that will be coming soon as well.


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