Posts Tagged ‘DualMiner review


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.


In our article about our first impressions from the Gridseed 5-chip Scrypt Asic earlier this month we were not very happy with our initial experience from the device. It seems we’ve got one of the earlier builds that were not very well built and the software for using them was also at a very early stage. Today however things look much better, we just got a new unit that we have ordered and it is much better built and uses the STM32 Virtual COM port driver instead of the CP2102 USB to UART Bridge Controller that our previous unit had.


We have tested the new ASIC device and it works just fine with the STM32 drivers installed with the modified for low power usage cpuminer for Scrypt mining by giving the virtual COM port number of the device. The ASIC also worked just fine when we have replaced the STM32 vitual cOM Port driver with WinUSB using Zadig to use cgminer 3.7.2 for Scrypt mining on the ASIC. We still haven’t tried using the new 5-chip Gridseed ASIC device to work in dual mining mode with TLC and BTC mining running at the same time as apparently the dual mining method that have already described for our older ASIC using the CP2102 USB to UART Bridge Controller is not working for devices with STM32 Virtual COM port drivers, so we’ll be getting back with more details on that later on when we figure it out.

For the moment however we are much more satisfied with the newer revisions of the 5-chip Gridseed LTC/BTC ASIC devices, especially when we take into account the improvement of the software support side for them in the last few days.


The 5-chip Gridseed GC3355-based ASIC devices that support Dual Mining for Bitcoin and Litecoin are not that easy to be used in the Dual Mode, because you need to have two different software miners running at the same time. There is a bit of specifics in what and how you need to do in order to mine both BTC and LTC at the same time and after a bit of tinkering we have managed to finally make things work as they should under Windows. You need to download a special modified version of cpuminer for Scrypt (LTC) mining and a modified version of cgminer for SHA-256 (BTC) mining. We have compiled the two software miners and you will find the download links below. You will also need the Zadig software in order to replace the virtual USB to COM driver with WinUSB driver for the cgminer to detect and work with the BTC mining side of the ASICs.


– Download and run the latest version of Zadig
– From the Zadig interface select Options and choose List All Devices
– From the Dropdown list of devices select CP2102 USB to UART Bridge Controller and click on Replace Driver with the WinUSB driver selected
– If you have multiple 5-chip GC3355 DualMiner USB devices connected you may need to repeat the procedure for all of them
– Download, edit and run the BTC.bat file from the modified cgminer 3.8.5 for the Gridseed ASICs to start the miner working on BTC
– Download, edit and run LTC_ONLY.bat file from the modified cpuminer for Gridseed ASICs to start mining for LTC (check what your COM port is and edit it). You need to add the parameter “dual” (without the quotes and two dashes in front) to the command line in order for the Dual mode mining to start working

It seems that there are some ASIC devices that may be using different virtual USB to COM drivers other than the CP2102 that our unit has (for example ST32 Virtual COM Port), unfortunately we don’t have any of those to test with. You can however try to make things work by replacing the other driver with WinUSB, just select the right name from the dropdown box (do not try to rename drivers, it is pointless) and Replace it with WinUSB (you may need to unplug and plug the USB cable to the miner after that). If after installing the WinUSB driver over the virtual USB to COM driver the ASIC does not work with cgminer, you just need to uninstall the driver from the Device Manager and unplug/plug the USB cable to the device for it to install the original USB to COM driver and it should be functioning again with cpuminer (note that this way you may have it running on a new COM port).

This is it, you should have the miner running both SHA-256 (BTC) and Scrypt (LTC) mining withe the two software miners and the total power consumption should be about 60W. Note that you may need to lower the operating frequencies a bit for when mining the Dual BTC/LTC mode as the chips get hotter. If you want to mine only BTC you can stick only with running the modified cgminer, for LTC only you need the modified cpuminer without the dual option in the command line. The most attractive aspect of the Gridseed 5-chip GC3355 ASIC however remains their very low power consumption for Scrypt mining only mode, so think again if you really wan to run them in the Dual Mining more or for BTC only and not in LTC only mining mode instead.