Posts Tagged ‘Scrypt ASIC


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.


Yesterday in our first impressions from the Gridseed 5-chip Scrypt ASIC device we have shared that the modified version of the cpuminer software is not reporting local hashrate. This is a problem as you can hardly know what is your current hashrate, especially when you start overclocking the device to get some extra performance out of it. You need to rely on information reported by the pool about your worker’s current hashrate, but these tend to often report lower or inaccurate results than actual hasrate. This is due to the fact that pools base the reported hashrate on the submitted shares for a given period of time, so result can vary. We can report that the average hasrate we are getting from our 5-chip Gridseed DualMiner ASIC device in terms of Scrypt mining performance to be hovering around 300 KHS with the stock frequency of 600 MHz that the five Gridschip GC3355 chips inside run at.

We could get the chips to run at about 850 MHz, but they were giving out quite a few HW errors, at least visually as the cpuminer software does not report actual number of stale shares or HW errors that the device makes. Seeing a lot of the red error messages means you are probably getting a lot of HW errors and should try reducing the clock frequency with 50 MHz or more. With 800 MHz the device was running more stable with much less HW errors, however this result was achieved with the use of the standard cpuminer software supplied with the device. Apparently this version of cpuminer had a bug and did not disable the BTC core and as a result mining Scrypt only you can get up to about 60W power consumption. By using the newer fixed cpuminer for Gridseed the power usage got down to the 8-9W range and we could overclock the device at 850 MHz with more stable results and very few HW errors. With 850MHz clock we got pools to report hashrate going up to about 400 KHS which is definitely a nice improvement though the newer version of the cpuminer still does not report local hashrate, so it is hard to get more realistic rate for the performance of the device when overclocked.

If you wan to overclock the Gridseed ASIC devices you need to use one fo the preset frequency values as they will not accept just about any frequency that you send to them. The lst of accepted frequencies consists of the following values: 250, 400, 450, 500, 550, 600 (default), 650, 700, 750, 800, 850 and 900 MHz. It is possible that with the version of cpuminer linked above that ensures low power consumption the ASIC devices may be ale to run pretty stable even at 900 MHz, however we still haven’t extensively tested that. Still even when using 850 MHz with about 400 KHS does not sound bad at all as compared to the claimed stock 300 KHS at 600 MHz.


Yesterday we have received our order of a single 5-chip Gridseed DualMiner device that is capable of Scrypt mining with a hasrate of 300 KHS as per the deice description, so we have already played with it for a bit and are ready to share what are our first impressions. A few days ago we have also shared our First Impressions from the DualMiner USB Scrypt ASIC that uses a single Gridchip GC3355 processor. The single chip device did work pretty well and although it needs a bit more improvement on the software side, it is well designed and works well in terms of hardware. So we were eager to try out the more powerful 5-chip version that we actually don’t know how to call exactly yet – Gridseed Golden Orb, Gridseed 5-chip Dual Miner, Lightningasic DualMiner it goes by all of these names with some variations in the color of the cooler – gold, silver, or red. The hardware inside remains the same however, capable of mining BTC and LTC at the same time or only Scrypt cryptos such as LTC with a higher performance then when working in dual mining mode. We don’t care about the BTC mining capabilities of the device, so we are going to focus only on the LTC (Scrypt) mining capabilities and performance.


From the outside the miner looks pretty good, so we have opened it to see what is the build quality inside the device – checking the components and the cooling design. Unfortunately we cannot say that we are happy from what we saw inside. While the PCB design is good and seems well made, the additional components on top and the wiring disappoint. We see masking tape used to insulate components like for example the USB to COM board, amateurish solution for the button next to the adapter power socket etc. Furthermore our unit had two of the wires from the USB to COM board squashed by the bottom part of the cooler over one of the Gridseed chips. This could cause issues with cooling and can also create problems with communication between the device and the computer feeding it with work, so we had to fix some of the wiring and insulation in order to avoid possible problems in the future. We can say however that we do not really like the build quality for something that is currently sold quite expensive, it seems amateurish and like it has been assembled in someone’s garage without adequate quality control. We really expected more, especially after seeing how good the single chip USB miner was made…


After fixing the hardware inside the miner it was time to fire up the device and try it out. So we had to look for some instructions how to use it as well as drivers and mining software (no documentation or software was included). We actually had some trouble having the miner properly recognized on half of the computers we have tried – the drivers did not function properly or did not assign a COM port for the device – it is connected via a USB port. Then to our surprise we’ve had to use a modified version of cpuminer that will work with the device and that software is really lacking advanced features that are found in the likes of cgminer for example. The miner software even does not give you a local report on the actual hashrate of the device, it only shows 0 KH/S, so you have to rely on the hashrate reported by the pool. There is also no adequate information about stale shares or hardware errors, so on the software miner side there is much work to be done for proper user experience – we need at least a recent version of cgminer modified to support the ASIC device.


Moving to the power consumption of the 5-chip Scrypt ASIC miner. By specifications the device should consume about 8W for Scrypt only mining and 60W for Scrypt and SHA-256 (LTC and BTC) combined mode. We are only interested by the Scrypt mining functionality of the device, so we expected to see very low power consumption, but to our surprise the watt meter showed 56W. It seems that even though we are not mining BTC with the miner that functionality is still active and the miner consumer power as if the device is working in both BTC and LTC mining mode. We’ve read that there is apparently an update released to fix the power consumption issue, but only released as a source code for the miner and you need to be able to compile it yourself – hardly anything that most miners are able to do by themselves.

So to conclude our initial impressions. It seems that these 5-chip Gridseed Dual Miners are far from ready for release to end users, however the company (companies) making them have rushed them on the market due to the user demand. They do not seem well enough built with good quality control, the mining software is in a very basic form just to say it is available and works. There is no detailed documentation for setup and use, so you will have to figure some things by yourself… not to mention any support, so if you have a problem you will have to rely on the mining community for help. It seems that these 5-chip Gridseed ASIC devices are not even in Beta, they are more like an Alfa stage product rushed to the market. We suppose that Gridseed did not even consider using these as a separate units, but had in mind to sell them in packs of 10 or 20 orbs with an additional controller that they will be connected and controlled from. We’ve ordered a single unit just to try it out before deciding is it is worth go for a 10 (3 MHS) or 20 unit (6 MHS) solution, but after reading about issues people are having with these and having issues ourselves with the single orb devices we can say that we are not happy with what we got for our money. We expected much more and actually a finished product, not some half baked solution that you can hope will work somehow and not cause you issues. We cannot recommend to an average user or miner these devices at all, if you are a technical guy with a lot of experience and knowledge in mining and miners (including software) you might like the challenge however. The single chip DualMiner USB ASICs however are a much more finished and user friendly product, so you might want to check these out for now and stay away from the bigger 5-chip devices until they become a more complete and properly working solutions.