The Antminer S7 was manufactured by Bitmain and is the predecessor to the S9. Since the S9 arrived, many miners have upgraded, flooding the market with relatively cheap used S7 devices.
Although the S7’s hash power is only around a third that of the S9, due to the lower cost and the fact that many second-hand units come with a PSU pre-bundled, you may see a faster return on your investment than with the S9. The S7 may also generate less heat and noise than the S9.
If you do decide to purchase an S7, be sure to check how long it’s been in operational use to decide how reliable it might be, and furthermore, check the seller’s refund policy in case it develops a fault after you buy. If the unit does come with a PSU, make sure it’s a good quality effort for maximum energy efficiency, such as Bitmain’s own AWP3++ power supply which also works with the S9.
Even with a high-end PSU, the S7 is still not as energy-efficient as the S9 – on average it consumes 0.25 Joules of power per Gigahash. The S9 is over twice as efficient, requiring less than 0.1. You may still be able to generate a reasonable profit with the S7 if you buy more than one unit and/or use renewable energy such as solar power.
- Cost: Varies
- Power usage: 1,293W
- Hash power: 4.73 TH/s
- Daily profit: 0.00061590 BTC