New Voltmod Update for the Gridseed 5-chip BTC/LTC ASIC Miners

29 Mar
2014

gridseed-asic-voltmod-v3-overclock

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.

cgminer-1050-voltmod-results

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.



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10 Responses to New Voltmod Update for the Gridseed 5-chip BTC/LTC ASIC Miners

jamie

March 29th, 2014 at 23:27

Thanks for this!
I was following the mods on bitcointalk but found it quite hard o read, the way you have explained it here I found it to be very easy to comprehend.
Your statement about the increase in wattage is a very good point and I did point out the same thing on the mod thread that it was pointless to go to such high voltage as that is counter productive.
Staying below the 10w is the goal indeed.
Do you reccomend runing it with the fan once modded like this?

Not Available

March 30th, 2014 at 03:12

It would be great, Admin, if you could at least credit the thread you are pulling this information from. There are several hardworking people who are spending their time and risking their devices to provide the information you are sourcing from.

The least you should do is give them credit in your article.

https://bitcointalk.org/index.php?topic=519112.0

Miner

March 30th, 2014 at 13:46

Thanks for the update. I realize all this testing takes A LOT of time but I be most interested in seeing some results of a volt modded GS running in dual mode to see if it could help with stability at freq 800 or 850 in dual mode.

admin

March 30th, 2014 at 14:50

Miner, doing voltmods and using the devices in Dual Scrypt and SHA-256 mining mode is not recommended. The increase in power consumption can lead to damage of the units or problems with the power supplies used. The Gridseed ASICs have a lot of headroom for increase in voltage and overclocking in Scrypt only mining mode due to the very low power usage in that mode alone.

Not Available, we have linked the source in our first voltmod article that also includes our own experience based on what the community has discovered so far and since then we have been linking back to our previous articles and have been risking our hardware as well in trying various things and reporting our own findings as well. We are reporting our findings based on modifying our own hardware and sharing the results here, if you’ve been following the blog you would’ve seen that.

Miner

March 30th, 2014 at 15:24

Thanks for the info. Good to know. Based on my dual mining results and what volt modded GS Scrypt miners have posted, volt modded GS Scrypt mining produces just about the same net income as GS dual mode mining at current difficulties. However, you don’t need as many power supplies though so there is both savings on hardware purchases and heat produced in your mining room.

Rowan

March 30th, 2014 at 20:11

Many people in the thread claim they are getting better “reported” results but according to their pools, it doesn’t seem as if the miners clocked past 850mhz are actually submitting noticeably more shares than an unmodded 850mhz gridseed. I was surprised no reference to this was made in this article.. or perhaps I have misunderstood the thread discussions?

admin

March 30th, 2014 at 20:45

Rowan, we have so far gone up to 1050 MHz and we are getting performance that is close to about 440 KHS, though at 1025 MHz with no HW errors the actual performance we are also getting is also close to that value. Some people claim of having gotten even higher with stable hashrates of about 500 KHS, by significantly increasing the voltage and the total power consumption. We have not yet tried going further in overvolting and overclocking that the mod described above, so we cannot confirm that. The fact that the reported increase in hashrate is achieved with about tripling the power consumption however does not make it very interesting to go further on the long run, still we are probably going to try that just for a test.

Rowan

March 31st, 2014 at 19:11

Admin, when you say “performance that is close to about 440 KHS” – how are you measuring the performance? Is it based on successfully submitted shares over a period of time, or just the local/pool reported hash rate?

admin

March 31st, 2014 at 22:18

Rowan, both local and poolside results, using scryptguild as pool with 64 worker difficulty.

JohnS

April 1st, 2014 at 20:11

I have a slight mod on my gridseeds and I am running at 404.4 KHS this is at 950 pool side is close. Been running for around 10 days with 9 Hw errors no more then you would see with the miner clocked at 850.

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