Litecoin Mining : Optimal thread concurrency for CGMiner

Litecoin Mining : Optimal thread concurrency for CGMiner

Litecoin-Mining-Optimal-thread-concurrency-for-CGMiner

Litecoin is based off the ever growing Bitcoin that uses an alternative memory hard hashing algorithm called Scrypt. Basically, it is a digital currency with no central authority. Transactions are confirmed on the network of users that employ it, and awarded with Litecoins for work done, which is what mining Litecoin is all about. GPUs are ideal for mining Litecoin because it have such a fast memory with bandwidth in the hundreds of Gigabyte/sec.

 

The most impacting factor for hardware errors and hashrate is the thread_concurrency (TC). And for some cards, the ratio of core speed to memory speed is the second deciding factor. The most common value for optimal TC settings are in multiples of 64, but the range vary for each brand and make. The ratio of core speed to memory speed is typically 0.8 or lower for 5xxx and 6xxx cards and 0.7 or lower for xxx cards. However, some instances does suggest that not all 7xxx series cards falls into this range and may have a different ideal ratio altogether.

 

Recommended thread concurrency

5xxx cards

You can tweak for the optimal TC value in the range of 1536 to 8192 in multiples of 64. Some found good results by multiplying the config core with 4 or 5. You can look up the value from the table here: http://en.wikipedia.org/wiki/Evergreen_(GPU_family).

 

Recommended TC value:

  • 57xx cards: 2368-4096 (3200 is common)
  • 58xx cards: 4096-8192 (5600, 7168, and 8000 are common)
  • 5970 card: 4096-8192 (5632 and 8000 are common)

 

6xxx cards

You can tweak for the optimal TC value in the range of 1536 to 8192 in multiples of 64. Some found good results by multiplying the config core with 4 or 5. You can look up the value from the table here: http://en.wikipedia.org/wiki/Northern_Islands_(GPU_family).

 

Recommended TC value:

  • 67xx cards: 2368-4096 (3200 is common)
  • 68xx cards: 3008-6144 (4800 is common)
  • 69xx cards: 4096-8192 (5600, 7168, and 8000 are common)
  • 6990 card: 4096-8192 (5632 and 8000 are common)

 

7xxx cards

Usually the optimal TC value for 7xxx series cards are slightly below 64 * bus width of card. For a 7950, that would be 64 * 384 = 24576 (21712 and 24000 are common). You can look up your bus width here: http://en.wikipedia.org/wiki/Southern_Islands_(GPU_family).
Recommended TC value:

  • 7770 cards: 8000
  • 7870 cards: 15360
  • 7950 cards: 21712 and 24000 are common
  • 7970 cards: 22392

 

Why is there no ASIC for Litecoin mining yet

The idea of Scrypt algorithm is that the algorithm is memory intensive so that  the gains from a Litecoin ASIC will not be as dramatic as with Bitcoin ASICs as scrypt is intentionally slower to hash, and so can get expensive to go ASIC. But as it gets more popular you can bet companies will create ASIC devices specifically to mine Litecoin.


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