Overclocking Your Bitcoin Miner

The name of the game in mining Bitcoins isn’t CPUs, GPUs, or even FPGAs. Now, hardcore miners are moving on to custom ASIC chips like the Block Erupter, For around $100 USD, you too can mine Bitcoins at 300 MH/s with 2.5 Watts of power and a single USB port. This speed isn’t enough for some people, like [Jeremy] who overclocked his Block Erupter to nearly twice the speed.

[Jeremy] begins his tutorial with a teardown of the Block Erupter hardware. Inside, he found a custom ASIC chip, an ATTIny2313, a USB UART converter, and a voltage regulator for the ASIC. By changing out the 12 MHz crystal connected to the ASIC and fiddling with the voltage with a trim pot, [Jeremy] was able to overclock the ASIC core from 336 MHz to 560 MHz. Effectively, he’s running two Block Eruptors for the price of one with the potential to actually make back the purchase price of his hardware.

It must be noted the 560 MHz figure comes from replacing the 12 MHz crystal with a 20 MHz one, and this mod only lasted about 20 minutes on [Jeremy]’s bench until the magic blue smoke was released. He recommends a 14 or 16 MHz crystal, netting a new speed of either 392 MHz or 448 MHz for a stable mod.

38 thoughts on “Overclocking Your Bitcoin Miner

  1. So If he left it stock and let it run for an hour he would have been ahead of the game. How long will it take for the next one to make up the cost of the one he killed?

    This is why you slowly turn up the wick to see how fast you can overclock a device, instead of attempting to run it at nearly double factory spec right out of the gate.

    1. I did start off slow with 12.5mhz, then 13mhz and 13.5mhz. Then I found a 15.36mhz crystal on a scrap board i had laying around. After playing around with that for a day being semi stable I moved on to 16mhz. I couldn’t find any other crystals between 16-20mhz so i bit the bullet and went all out. This wasn’t a 1 day thing, I spent almost a week testing things out and changing the crystal circuit. One thing I want to try is to abuse a ATtiny24 for its crystal oscillator circuit and see if I can steal the clock signal off it :)

  2. The problem with overclocking this type of system is verifying it is working correctly when you overclock it. With a computer you can interact with it and it is quite obvious when it doesn’t work right. With a bitcoin miner it just sits there and it may actually pass over a valid bitcoin because it isn’t working right.

    1. Simple. Just attach your miner to a bitcoin mining pool, and look at the pool estimate of the hashing speed. The nice thing about bitcoin mining is that a small amount of errors, say 1%, is perfectly acceptable.

        1. I don’t think you understand how Bitcoin actually works. A roughly 60% gain in clock rate is very desirable even at a 1% error rate, since you still have a much higher probability of producing a block.

        2. All that matters is how many good hashes per second you can do. If a standard device does 300 MH/sec with 0% errors, and an overclocked device does 400 MH/sec, with 10% error rate, it’s still doing 360M good hashes per second, which is better than 300M. An error in one hash does not affect the other hashes. In a mining pool, you get credited for each share (on average it takes 4GH to produce one share).

          1. Er actually that is NOT correct…..
            All that matters is the NUMBER OF NONCES produced that meet/beat the difficulty.

            you could have a device capable of 3TH/s but if it produces ZERO matching nonces it is WORSE than a device running 300mh/s that produces three nonces.

            The problem with over clocking is that you do not know how many QUALIFYING nonces you are trashing..
            The ONLY way you can measure it is to have a device that processes exactly the SAME work at a much slower rate to compare against…

            A working example…
            I ran an FPGA ..way…way over clocked, the ‘error’ rate was 0.2%, that is to say out of 1000 nonces produced 2 were bad…

            BUT on checking with chipscope, I found that the over clocking was setting the high bit on during the comparison to meet the diff1 over 20% of the time…

            Which means that my loss was actually 20.2% , of GOOD nonces…
            Externallly it looked like 0.2%… but internally (something you cannot see without an internal probe) it was >20%

            Better you actually UNDERSTAND what you are talking about, before commenting….

          1. Indeed. At the current rates, 300MH/sec will get you $3 in a week, but earnings are dropping about 10% per week. Extrapolating that curve, you can expect something like $30 total return.

    1. I have no exact reason for the failing of the asic. Although I have a feeling that the 5v clock signal boards may have been a ticking time bomb waiting to destroy the chip.

      My next test I am planning on using a raspberry pi with voltage sensors on the asic core voltage lines and i2c temp sensors to monitor the stats of the block erupters at all times :)

  3. Lot of very poor research in that article. Arctic Silver isn’t conductive and hot glue is a godawful way to attach a heat sink. Not only is it flexible at room temperature which reduces pressure against the chip, but loses bond strength as the temperature increases. I’ve seen half a dozen people use hot glue to attach sinks only to have them fall right off when they need them most. The fact he didn’t bother to monitor the temperature as he increased the overclock is also disturbing as he has no idea what actually killed his Erupter.

    1. I remember from past experience that various versions of Arctic Silver were electrically conductive.
      From their website
      “Arctic Silver 5 was formulated to conduct heat, not electricity.
      (While much safer than electrically conductive silver and copper greases, Arctic Silver 5 should be kept away from electrical traces, pins, and leads. While it is not electrically conductive, the compound is very slightly capacitive and could potentially cause problems if it bridges two close-proximity electrical paths.)”

      So even with the latest version they have out, you run into issues with messing up the capacitance on the board.

      1. I have a cooling solution. It is actually cooling 3 block erupters together, and your points about thermal glue are pointless, just screw the device to the heatsink. anyway I would love to modify my erupters email me for more details.

    1. Over a year @ the current difficulty trend. The price is way too high on these right now once some competition get into the market prices should go down. I paid a bitcoin for each of mine several months back and have yet to mine a bitcoin between the two even after overclocking.

  4. Many people including myself are just starting to hear about Bitcoins even though they have been around since 2008-2009. They are a very new “currency” and will allow you to profit without ANY fees of transfer, any freezing of funds, doesn’t require banks and is currently feared by established financial institutions to the way of trying to ban it. The funny thing is that is it`s impossible to ban or prohibit because no one owns it!

    There are a group of clever developers are working on a tool that will allow people to make bitcoins every single day! There is a nice short to the point video that explains the “Human Greed” factor and why this is an entirely new and unexplored market!

    This is unlike anything you have ever seen or heard off and it makes perfect sense that early birds knowing this info will make a lot of money off the backs of people that come into a new moneymaking market too late. The beauty of this is that you stay anonymous and in nowadays world flying under the radar is important. The recent scandals of governments spying on its citizens are making “transparency” a scary thing so don`t let anyone meddle in your private affairs!

    There is a free presentation seat to be grabbed so you can be the first to learn more about this bitcoin robot that is due to be released very soon to a small circle of people that follow its development. Check it out now: http://ezhomefunds.com/btcsm

    1. Trading bots only work for short periods of time, they lose their effectiveness quickly as the market changes. I’ve traded the forex market for quite some time now and these bots are just a gimmick.

  5. I have a Dell with a Intel HD Graphics 2500. I was wondering if this is the CPU or a separate chip on the motherboard. I know i should use a graphics card but im going to start out small and then buy one. When I started to mine i Noticed a chip on my motherboard getting Very hot. Would that be the GPU? It has no fan so if it is i want to put one in. Could anyone help?

    1. Honestly, you’re wasting your time mining with an intel graphics on-board vid. Its a chip on your mobo, but really only super high end graphics cards give you any kind of real POWER for mining.
      The discussion here is about a specific piece of hardware called an erupter – its a little usb chip that plugs in and will dedicate itself to mining – at around 300 M/H per second…(by comparison, I originally used guiminer for fun just to see what I could get on an intel hd 4000 and I got around 17 M/H per second). Also, look into what bitcoin mining pools are – going at it alone even WITH the right hardware will get you nowhere.

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