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"Eth-Death" - Understanding Ethash GPU VRAM Requirements


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    Are you suffering from miner crashes and/or receiving DAG errors when trying to mine Ethash?

    • Your GPU's may be suffering from "Eth-Death."

    Before we can understand what "Eth-Death" actually is, we need to first cover one of the key components in the mining of Ethash:

    The DAG File

    DAG stands for "Directed Acyclic Graph". It is used in all Ethash coins, like Ethereum, Ethereum Classic, Metaverse, Ubiq and other coins to provide a proof of work. The DAG file is generated every mining epoch and it increases from epoch to epoch. It is very important to know current and future size of DAG file because it has a huge impact in relation to usable mining hardware (i.e. GPU's).

    This DAG file is loaded (and stored) directly to your GPU memory (VRAM) during the mining process. If, however, the DAG file size happens to be larger than your GPU's VRAM capacity, then the file cannot be loaded and mining cannot happen. This usually results in DAG errors being reported by the mining software or (worst case) complete crashing of the miner and/or rig.

    Since increasing a GPU's VRAM capacity is not an option, those GPU's, who do not have the necessary VRAM capacity, are technically "dead" to mining the Ethash algorithm. (i.e. They have suffered "Eth-Death")

    Want to check out what the current DAG file size is? There are plenty of calculators on the internet that will work out the value for you.

    "Wait... the current DAG file size is only 3.91GB. My GPU's are 4GB..."

    • Let me stop you right there. Your "4GB" GPU's are most likely not rocking the 4GB you think they are.

    When it comes to computer hardware, end-item manufacturers "round up" when it comes to marketing. Don't confuse this with the whole "1000 is actually 1024" thing. This has more to do with a manufacturing practice known as "product binning".

    In our specific case, we have two major players involved: 1. The chip manufacturer and 2. The GPU manufacturer.

    Chip Manufacturers (Samsung, Micron, Elpida, Hynix, etc...)

    Memory chips, due to their complexity, are not able to be made to exact specs/sizes. After the chips are made, the manufacturer will machine test them to see how much is addressable and usable (along with other quality checks). After testing, the chips are then sorted into groups based upon those results. (Any chips that fail to meet the manufacturer's thresholds/standards are usually recycled back into the process to be made into new chips.)

    The chip manufacturer prices out these chip groups according to their quality and sells them to the end-item manufacturers in bulk.

    GPU Manufacturers (Asus, EVGA, MSI, PNY, etc...)

    As already mentioned above, these manufacturers buy the chips in bulk from the chip manufacturers.

    Ever notice how these guys don't ever release just a single RX570 or GTX1070?... Also, ever notice that the different variations of the same base GPU have different specs and prices?

    That's because they're using better parts... more specifically, better chips. The lower priced GPU's end up with lower quality chips while the higher priced GPU's end up with the higher quality chips.

    At this point, the marketing departments take over and work their "magic" with number rounding. Since nobody would want to buy a 3.92GB GPU, they just round it up and market it as a 4GB GPU. Basically, they just say "Close enough!" and ship them out.

    "Okay, but if the GPU has 3.92GB and the DAG is only 3.91GB... I should still be good to go, right?"

    • Maybe... it's a bit more complicated than that...

    You still need to account for the GPU's resource overhead. Although it's not a lot, it still exists. A GPU still needs resources even if it's just sitting idle.

    Do you have a monitor connected to this GPU? If so, producing an output to a monitor requires even more resources.

    Most of the mining software's "work" code is also loaded into the GPU's VRAM for faster execution... blah, blah, blah.

    The main point here, is to know that even the basic operation of the GPU uses up resources - resources that could otherwise be put towards mining. Without knowing exactly how much this "total overhead" is, it starts to get really hard to tell how much impact, if any, it may have towards mining.

    However small it may be, when we're dealing with the difference between 3.91GB and 3.92GB, the GPU's overhead could be just large enough to push the GPU over the threshold and cause an earlier than expected/calculated "Eth-Death."

    "So I'm stuck and all is lost?!"

    • For Ethash, Yes.

    There is no fix for a GPU that has suffered from "Eth-Death". Unless something changes within the Ethash algorithm in the future (very unlikely), "Eth-Death" is permanent.

    Some of the Ethash mining software developers have been actively trying to delay "Eth-Death" as long as physically possible by optimizing their code. Although these tweaks are really "hit-or-miss" and only work for some, they are worth trying if you're trying to squeeze as much ETH from your GPU's as possible.

    One that seems to have worked for a few is Phoenixminer with the following additional flags: -altinit -rvram 1

    Understand that these are not cures... they're just a delay, at best - attempts at delaying the inevitable.

    • For mining in general, No.

    The "sun may have set" on your GPU's dreams of forever mining Ethash, but it doesn't have to mean the end of mining. There are many other algorithms/coins out there that your "4GB" GPU can still work on.


 



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