All About BTC, LTC, ETH mining as well as other alternative crypto currencies
Time for another take on the voltmodding of the Gridseed 5-chip BTC/LTC ASIC miners with the latest development surrounding the voltage modifications of the devices. In our previous experience in doing a hardware voltage modification we were able to easily get up to 950 MHz overclock from the 850 MHz maximum overclock with the default voltage, or with other words up to about 404 KHS hashrate. The previous voltage mod we did included soldering two bridges on the board of the ASIC, the new one we have tried also includes replacing two resistors with other values. So doing 4 modifications in total, you can see them marked on the photo above with the hope of getting higher hashrate than with the previous voltage modification.
The two zeroes in green on the right of the photo mark the places where you need to solder the bridges, we have used small pieces of very fine 30 AWG kynar wire, so that we could easily remove the bridges should we decide to remove the hardware modification. The resistor on the lower left side is 36 kOhm and we have replaced it with a 39 kOhm 1% 603 resistor (the standard one is 402 size, but we did not have the needed value in that smaller size, so we used the slightly bigger 603 size). The modification in the top left side of the resistor marked R211 has been done using pencil to change the resistance, however we went the better way and have tried replacing the resistor. The standard resistor used is a 402 size with 3.65 kOhm (1.1V PLL), we have tried replacing it with a 2.4 kOhm (1.0v PLL) and 2.7 kOhm (1.025) resistors and left the 2.7 kOhm 402 1% one in the end.
After the voltage modification described above we have tested to see what results we can get in terms of further overclocking the 5-chip Gridseed ASIC devices. We were able to run the device at 1050 MHz or about 450 KHs hashrate with not so many hardware errors, and at a step lower at 1025 MHz with a hashrate of about 436 KHS the device was able to run with with no HW errors at all. A nice improvement with no significant increase in power usage, however you should be aware that the hardware modification is not easy at all and not everyone will be able to do it all by himself. The 402 size resistors have a length of about 1 mm and width of 0.5 mm, so they are really SMALL and hard to solder and you need to replace such resistors on the board. Also do note the fact that you can damage the device when trying to do the hardware modification, so be very careful and if you are not sure you will be able to perform the mod yourself, you better not start doing it.
Some users are already reporting in being able to achieve even higher overclocks by supplying more voltage to the chip, but with a significant increase in the total power consumption that apparently is multiple times than the normal power consumption in Scrypt only mining mode. This pretty much make such modifications pointless as you are getting something like 10-15% more hashrate at the cost of multiple times the power usage, not to mention the high possibility of seriously shortening the life of the devices. We are going to be playing a bit more with the voltage modification, mainly trying some more resistors to see if we can squeeze a bit more extra performance out of the Gridseed ASIC devices without increasing the voltages too much and staying close to the 10W power consumption.