Saturday, October 29, 2016

zcash mining

Zcash is the hottest coin this month, after going live on October 28th, following several of months of testing.  Zcash promises private transactions, so that they cannot be viewed on the public blockchain like bitcoin or ethereum.

I did not expect zcash mining to be immediately profitable, since mining rewards are being ramped up over the first month.  However the first hour of trading on Poloniex saw zcash (ZEC) trading at insane values of over 1000 bitcoin per ZEC.  Even after 24 hours, 1 ZEC is trading for about 6 BTC, or US$4300.  Despite the low mining reward rate, mining pool problems, and buggy mining software, I was able to earn 0.005 ZEC in one day with a couple rigs.

Zcash has both private address starting with "z", and public or transparent address starting with "t".  A bug in the zcash network software has meant problems with private transfers, so it is recommended for miners to use only transparent wallet addresses until the bug is fixed.  Miners using the "z" address have apparently had problems receiving their zcash payouts from mining pools.

I have been using eXtremal's miner version 0.2.2, which uses OpenCL kernels from the zcash open-source miner competition.  Windows and Linux binaries can be downloaded from, the pool the software is designed for.  I get the best performance with the silentarmy kernel, but with only one instance as running 2 instances results in a crash.  On Windows running driver version 16.10.1 I get about 26 solutions/s with a Rx 470.  Under Ubuntu with fglrx drivers I get about 11 solutions/s for both R7 370 and R9 380 cards.

I experimented with the worksize and threads values in config.txt, but was unable to improve performance compared to the default 256/8192.  Increasing the core clock on the R9 380 cards from 900Mhz to 1Ghz increased the performance by 3-4%.

Genoil has released a miner, but only Windows binaries with tromp's kernel at this time.  A version including silentarmy's kernel is in the works.

I was unable to find any zcash mining calculators, so I wrote a short python calculator.  Here's an example based on the network hashrate (in thousands) at block 1072, for a rig mining 140 solutions/s:
./ 1072 1840 140
Daily ramped mining reward in blocks: 308
Your estimated earnings: 0.0234347826087

At the current price of 6BTC/ZEC, the earnings work out to about US$100.  Even if the price drops to 3BTC/ZEC, the daily earnings are still more than double what the same hardware could make mining ethereum.  Apparently many other ethereum miners have realized this, since the ethereum network hashrate has dropped by about 25% in less than 30 hours.  I expect this trend to continue in the coming days, and eventually reach an equilibrium as the ZEC price continues to drop until it is below parity with BTC.

2016-10-30 update

Coinsforall is still having stability problems, and now 1 ZEC is worth about 1.2 BTC.  Therefore I've switched back to eth mining for all my cards except one Rx 470.  With Genoil's ZECminer I'm getting about 26 sol/s.  I started using, and after an hour of mining the pool has been stable.  Reported hashrate on the pool is about 12H/s, or half the solution rate as expected.