BTCB2 has hit the maximum 4x difficulty retarget twice in a row - it's still mineable due to its Diff by GPU/CPUSince the BLAKE2b fork the chain has never reached its ten-minute target:
period start difficulty factor previous period took
963,648 17,842,860 reset 572 h
965,664 71,371,438 4.00x 17.5 h
967,680 285,485,753 4.00x 54.7 h
A period is meant to take 336 hours. One of them closed in 17 and a half. As of block 968,851 the
last 144 blocks have averaged 116 seconds, and the next retarget is 845 blocks away.
This matters for one practical reason. The usual estimate - subsidy, times 144 blocks a day, times
your share of network hashrate - assumes the chain hits its target interval. It does not, so that
estimate comes out roughly four times too low. Use difficulty instead:
blocks per day = your hashrate x 86,400 / (difficulty x 2^32)
solo wait = difficulty x 2^32 / your hashrate
At difficulty 285,485,753 and a 3.125 subsidy that gives about 0.95 BTCB2/day for an Innosilicon
S11 SiaMaster, 0.18 for an Antminer A3, 0.0038 for an RTX 5090. No price in there - apply your own.
Worth knowing that "network hashrate" is ambiguous here: derived from the difficulty it is about
2 PH/s, measured from how fast blocks actually arrive it is over 10. Only the second describes what
is really out there hashing, and it is why the difficulty has that much catching up to do.
Two things if you want in:
Sia-generation ASICs mine this on stock firmware. An Antminer A3, an S11 SiaMaster, an Obelisk SC1
or an iBeLink BM-S3 connects the way it did to a Sia pool - no reflash, no patched software. If you
rent hashrate, rent it under Blake2B rather than SHA-256.
There is a free MIT-licensed miner for GPUs and CPUs at
github.com/ocminer/supryolo - no developer fee, and
not my project. A Ryzen 9 3950X does 367 MH/s on it, which is a valid share every twelve seconds.
Check https://b2pool.io. It found its first block on 7 September at height 968,704, at 32 %
effort. Stratum in Frankfurt, Helsinki, Chicago and Kyiv - take whichever pings lowest. The calculator there uses the
formula above with live figures if you would rather not do it by hand.
