When mining “Memory Hard” algorithms such spil the Dagger-Hashimoto which is what is used by Ethereum, one of the mechanisms used to make this algorithm ASIC (Application Specific Integrated Circuit) resistant is the dynamic DAG verkeersopstopping. The DAG opstopping grows overheen time to both increase the mining difficulty and to present an everzwijn moving target that requires more and more on-board movie card memory to be able to effectively mine.

Early reports of older cards such spil the, HD6950, left owners incapable to mine due to the fact that while they technically had enough memory Two GB (2048 MB) of on-board RAM, they could not allocate it all at once, thus becoming incapable to mine the algorithm. Recently with block 1,400,000, this problem has now enhanced to affect even more latest Two GB GPUs. An error similar to the one below is displayed once this threshold has bot reached:

Creating one big buffer for the DAG

Allocating/mapping single buffer failed with: clCreateBuffer(-61). GPU can’t

allocate the DAG te a single chunk. Bailing.

This is a known punt that the Ethereum developers have developed a work-around for, however it is not yet ter any released version of miner software. The problem is that while there is technically enough memory, the card cannot allocate it all ter one go, therefore it errors out.

setx GPU_FORCE_64BIT_PTR 0

setx GPU_MAX_HEAP_SIZE 100

setx GPU_USE_SYNC_OBJECTS 1

setx GPU_MAX_ALLOC_PERCENT 100

setx GPU_SINGLE_ALLOC_PERCENT 100

ethminer –farm-recheck 400 -G -F http://172.16.0.225:8546/miner-09 –cl-global-work 16384 –cl-local-work 256

The setx is a instruction for Windows to set x(environmental) variables for the system to use. Ter this case wij are setting GPU variables to permit the allocation of memory to the maximum available. While some miners have bot using a subset of thesis variables since the scrypt mining days, the last variable “GPU_SINGLE_ALLOC_PERCENT” seems to be the one wij will need to address the latest error, ter that it permits a single allocation (thread) to use up to the maximum amount of available memory.

A very geschreven overview of the variables and their available values are spil goes after:

  • GPU_FORCE_64BIT_PTR [0 | 1] – When set to 0 this setting permits access to 32-bit address space of memory

Three.8 GB. When set to 1 it permits access to 64-bit address space. While it may sound like a good idea to set it to 1, it may actually hurt show since then pointer access would require twice the number of clock cycles to accomplish than it would if left ter 32bit mode. Note: For gaming leave this set to 1, especially if you want to use all of your memory te 4GB+ cards.

  • GPU_MAX_HEAP_SIZE [0 – 100] – By default the memory made available to OpenCL is limited to just 50% of total GPU memory. With this setting it is possible to increase the amount of memory available up to 100%
  • GPU_USE_SYNC_OBJECTS [0 | 1] – Syncs the System CPU with the GPU deeds to improve show, 0 is thought to lock usage to a single CPU core while 1 is thought to permit access to numerous CPU cores. Since this is a undocumented setting, it is hard to tell for sure. If you see 100% CPU utilization, attempt the opposite setting, There is even some debate if this works with Windows at all.
  • GPU_MAX_ALLOC_PERCENT [0 – 100] – Maximum amount of memory that can be allocated globally. Needs to be equal to or higher than the next setting.
  • GPU_SINGLE_ALLOC_PERCENT [0 – 100] – Maximum amount of memory that can be allocated to a single process. This is limited by the above setting, so be sure to increase both.
  • The “timeout /3” is optional, and simply introduces a slight pause so you can observe for “Value successfully set” messages on launch.

    The final line is the familiar launch string for the Ethminer program. The settings are suggested for movie cards such spil the AMD R9 380 and AMD R7 370 series. A “farm-recheck” value of 400 has shown to be effective with cl-global-work values of 16384 and 8192 which thesis cards are capable of. The cl-local-work value of 256 is also optimum for thesis cards and can be set to match the ” CL_DEVICE_MAX_WORK_GROUP_SIZE” value spil shown below, te this case it is 256.

    You can also look at the “CL_DEVICE_MAX_MEM_ALLOC_SIZE” value, to see what the maximum DAG verkeersopstopping your card will support. Te this example I am using Two GB cards, with a maximum usable memory allocation of: 1878490204 bytes (1.878 GB) before I would be incapable to mine Ethereum with thesis anymore.

    The current DAG opstopping size is 1.384 GB ter size, providing thesis cards about 500 MB more ter DAG verkeersopstopping growth before they will no longer be able to mine Ethereum. Do note that there are other algorithms, such spil SOIL and EXPANSE that also use the Dagger-Hashimoto algorithm and are presently profitable to mine, so once this point ter time arrives it does not necessarily mean the Two GB cards become worthless, you would just need to switch to another profitable coin.

    Ethereum violates $1 billion te MarketCap, Bitfinex to start trading on Monday

    Related movie: How to do Digibyte Mining on GPU(Laptop/PC)


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