Has anyone else been following the recent launch of the new coin LBRY.io?
I have been keeping track of it on Bittrex just out of curiosity, and it serves as a prime example as to why GPU mining really needs to be seriously looked at before Zcash launch.
The LBRY platform itself or price is not important for this discussion: however what is notable is that the Developers claimed from the beginning that they wanted to be CPU friendly and only launched with a CPU miner. They even implemented a "mining slow start" for fairness. Then as you can see it only took about 4.5 days for a GPU miner to be developed by the public effectively shutting down anyone who was still mining with a CPU. I believe the LBC coin is based off of a version of SHA-256 so this result is not surprising.
As a CPU friendly / mining slow start for "fairness" coin this is a complete failure to mitigate the impact of GPU.
I don't think that this will be as extreme of a case with Zcash launch because @zooko and @str4d and team are using Equihash, but even in the Equihash whitepaper (section 6-b) it mentions a GPU advantage of a factor of 4:
b) Parallel sorting in practice: The observable speedup
on multi-core CPU and GPU is not that big. The fastest GPU
sortings we are aware of have been reported in , where
radix sort was implemented and tested on a number of recent
GPUs. The best performance was achieved on GTX480, where
2 30 32-bit keys were sorted in 1 second 6. The same keys
on the 3.2 GHz Core-i7 were sorted with rate 2 28 keys per
second , i.e. only 4 times as slow. Thus the total advantage
of GPU over CPU is about the factor of 4, which is even
smaller than bandwidth ratio (134 GB/s in GTX480 vs 17
GB/s for DDR3).
There are many farms out there like this:
that are very adept at developing GPU software and would love to point their machines at Zcash.
I just wanted to post this as food for thought, I know there are a few Github open issues that reference this topic so the Zcash team is aware of it, but none the less it is still a very real threat to the goal of Zcash as a truly decentralized system.