Antminer KA3 €1200/month! Antminer K7 €550/month! Test and review of the most profitable ASICs
In early 2023, two new Bitmain ASICs took the top of the profitability rankings: the Antminer KA3, which mines Kadena (KDA), and the Antminer K7, which mines Nervos Network's CKB. In this video (in French), we present both machines, show how to set them up, compare them with the competition and work out what they were earning at the time. We also give our view on the question of the moment: should you buy them right away?
Video from early 2023: the figures below, including the €1,200 and €550 per month in the title, date from that time. See "What about today?" at the end of the article.
Update: Kadena is dead. The organisation behind Kadena ceased operations in October 2025 and KDA lost more than 60% of its value within hours. The Kadena earnings and Kadena miners (Antminer KA3 and others) covered in this article are no longer relevant.
The Antminer KA3: 166 TH/s on Kadena
The KA3 was offered for pre-order in November, with delivery announced for December, and it arrived a good month late. It delivers 166 TH/s on the Kadena algorithm for a power draw of about 3,100 W. Bitmain specifies a noise level of 80 dB, which matches what we measured.
The gap with the competition is huge. Before its release, the most powerful machine on Kadena was the Goldshell KD Max, with 40 TH/s for 3,300 W. The KA3 draws slightly less power for about four times the hashrate, so it is about four times more efficient. As for the iBeLink released shortly before, at 70 TH/s for 3,000 W, it is roughly half as efficient as the KA3.
What the KA3 was earning
- Earnings: with electricity at €0.10 per kWh, about €1,440 per month, and €1,200 per month once electricity is deducted, i.e. about €14,000 per year.
- Purchase price: it had risen sharply. The machine sold for €12,000 at the time of our test, whereas it had been available for around €8,000, i.e. about €4,000 more.
- Return on investment: about 10 months at that price. With electricity at €0.17, the full residential rate in France, it went up to about 11 months: still a remarkably short payback compared with Bitcoin machines or machines mining ETC.
The Antminer K7: the CKB machine
The K7 mines CKB, the cryptocurrency of Nervos Network, which we covered in a dedicated video. It was doing very well too: about €760 of earnings per month, and €550 per month after deducting electricity at €0.10. Over a year, that roughly matched the price of the machine: our calculator gave a return on investment of about 8 months, and in any case under a year.
The profitability ranking at the time
In the ranking of the most profitable ASICs, the two new Bitmain machines were ahead of the Antminer L7, which mines Litecoin and Dogecoin and has been available for a long time:
- Antminer L7: around €15 per day, still an attractive return;
- Antminer K7: a little more than the L7;
- Antminer KA3: €40 per day, more than double.
We did not expect the KA3 to stay at €40 per day: we rather expected it to fall to between €15 and €30 or so per day. At the time of our test, Kadena's mining difficulty had not yet exploded, but it is the figure to watch: when it rises, each machine earns less and the payback time gets longer.
A standard setup
Both machines are set up like other recent Antminers:
- once the miner has started, find its IP address in your internet router's interface or with an IP scanner tool;
- type this IP address into your browser and log in with the default username and password;
- enter your pool and your wallet address;
- if needed, change the login password and update the firmware by uploading the file provided;
- fan speed is automatic by default, but you can set it manually.
Our advice before buying
- Wait on the KA3: at €12,000, we rather advised waiting a little than buying right away, to see how the machine's price and the network difficulty would evolve.
- Plan a suitable room: these machines reach 75 or even 80 dB. We advise against installing them in a garage or in a house.
- Lower your electricity cost: solar panels, EDF's Tempo plan (around €0.12 to €0.13 on average) or a business contract if you run a company.
- Keep in mind the risk of the coins you mine: KDA is not in the top 100 but not far from it, and CKB ranks around 200th. Both projects have potential, but they are not safe assets like Bitcoin: run your numbers, diversify and don't put all your eggs in one basket.
What about today?
Since this video, Kadena's network difficulty has risen sharply as KA3s arrived in large numbers. In October 2025, the Kadena company announced it was ceasing operations: the blockchain keeps running thanks to its miners and community, but the KDA price fell sharply. The monthly earnings quoted in the video are therefore no longer relevant, for the KA3 as for the K7: before any purchase, redo the calculation with current difficulty and prices.
To compare today's machines, browse our ASIC miners. No room suited to the noise of an ASIC? Have a look at our miner hosting, or contact us for advice before you buy.