All About BTC, LTC, ETH mining as well as other alternative crypto currencies
If you are using the 5-chip Gridseed ASIC devices in Scrypt only mining mode you probably already know that they are using about 8W of power when overclocked. But what about optimizing the power usage even more by removing the noisy fan that might be needed for the 60W power usage in Dual mode or the 50 and something in BTC only mode, but you can go without it in Scrypt only mode. So we did just that, desoldered the fan from the ASIC and ran the device in fanless mode. And surprise, surprise the total power usage without the fan gets down to just about 5-6W overclocked to 850 MHz, but what about cooling without a fan?
Running for more than 2 hours already the ASIC in fanless mode mining Scrypt has shown that it can do just fine with passive cooling. The maximum temperature was about 36.6 degrees Celsius at the hottest point with an ambient temperature of about 25 degrees Celsius. Don’t get the wrong impression from the thermal images, these temperatures for passive cooling are more than adequate and essentially the cooling radiator is considered cool, meaning that in Scrypt only mining mode you can do just fine with passive cooling at lower ambient temperatures. If you have multiple units together you might want to have a single big fan with slow rpm just to move a bit of air around them you you can be safe even when the summer heat hits.
A word of warning though, if you remove the fan from the Gridseed 5-chip ASIC devices and for some reason you start a miner for Scrypt that does not stop the BTC mining part or you start the dual mining mode you will have trouble with cooling the device and this can lead to a damage of the ASIC caused by overheating of the chips – most likely the first to blow up would be the voltage regulators. So be careful that you run only in Scrypt mode if going fanless and to use miners that do activate only the Scrypt mining mode and disable the SHA-256 one.
Today we have decided to compare the Gridseed 5-chip BTC/LTC Dual Mode ASIC devices in terms of thermal characteristics when operating in Scrypt only mining mode (~8W overclocked) and in Scrypt/SHA-256 dual mining mode (~65W overclocked). We wanted to see how good the massive radiator and high-speed cooling fan will be able to handle in the two modes and more specifically in the dual mode as it is apparently designed to cool the device properly with the high power consumption that it has when mining for BTC (SHA-256) and LTC (Scrypt) at the same time. So we put two ASIC devices next to each other, the one on the left is running in Scrypt only mining mode and the one on the right in Dual mode mining for BTC and LTC at the same time.
We left the devices to work for an hour before taking the thermal images in order to see what are the temperatures of the two miners. Note that the top of the devices does not seem very hot and the highest temperature is that of the cooling fan’s motor. You can however see that around the device running in Dual mode the temperature is higher due to the hot air that is being blown. Looking at the bottom part of the device however we can see more serious difference in the operating temperatures of the two devices. The highest temperature of the device mining in Scrypt only mode we measured is 32.1 degrees Celsius, the device in Dual mode on the right however shows very different results – the maximum temperature we have measured was 73.5 degrees Celsius. As expected the highest temperature measured is at the part where the 3 voltage regulators are located and while they are probably rated to work at temperatures of up to 100-120 degrees C they still do get quite hot as they do not have direct contact with the cooling radiator of the device. So if you plan on running the Gridseed 5-chip BTC/LTC ASIC in Dual mode you might want to consider adding additional small radiators for problem free operation in the long run. The maximum temperature of the Dual mode ASIC aside from the voltage regulator’s region was 44 degrees Celsius, so the cooling of the Gridseed GC3355 chips is more than adequate.
What we would recommend however if you are getting Gridseed 5-chip BTC/LTC Dual Mode ASIC devices is to stick to running them in Scrypt only mining mode where their real advantage is – high performance Scrypt mining hashrate with very low power usage… and no potential problems with the cooling either. Next up we are going to desolder the fan of the Gridseed ASIC devices to see how they will be handling passive cooling in Scrypt only mining mode.
You can read our first impressions from the DualMiner USB Scrypt ASIC here and now we took some time to take some thermal images of the miner to check the temperature adn what actually gets hot, so you can consider some extra cooling as well as to measure the actual power usage of these small USB-powered devices based on a single Gridchip GC355 processors for mining BTC/LTC. It seems that the DualMiner’s aluminum heatsink on one of the sides of the device is working quite well, the temperature it shows is quite even and goes to just aa bit short of 50 degrees Celsius. That is with the miner running for Scrypt only mining mode at 850 MHz with 70 KHS hashrate, we are not very mich interested in the combined mining mode where the device also mines for SHA-256 cryptos, note though that if you use the miner in dual mining mode it will get hotter.
The other side fo the device’s PCB is with the chips and the two things that get hotter as expected are the GC3355 processor as well as the controller chip, so you might want to add some small cooling radiators on them in order to get better cooling. Alternatively adding a small fan like a USB one to create a good airflow or combining both things will make sure that the miner will run for longer period of time at its maximum without giving you trouble. Again this thermal images shows the miner running in Scrypt only mining mode with temperature of the chips going as high as close to 53 degrees Celsius. If you run in Dual Mode however the extra 1W of power consumption that is expected from the BTC side might increase the operating temperatures with another 10-12 degrees on top of what we are getting with Scrypt only mode.
What about the power usage? Since these devices are designed to be powered by a USB port their maximum power usage should be no more than 2.5W (0.5A at 5V) and that can be reached in Dual Mining mode. The idle power usage of the device when it is just plugged in and running in Scrypt only mode is a bit high at 0.875W, and it only increases to 1.485W when you start the miner. So getting about 70 KHS of Scrypt mining hashrate for just about 1.5W of power consumption is a great result for the hashrate you are going to get, what is not so attractive is the price that these devices are still being sold for. Nevertheless we are very satisfied from how the single chip DualMiner SUB ASIC devices are made and work, so next in line for similar testing are the 5-chip Gridseed BTC/LTC ASIC miners.