The Bitmain Antminer KS3 is an air-cooled Kaspa miner and the first Kaspa machine Bitmain built, shipping since August 2023. It is designed for the kHeavyHash algorithm, which is what Kaspa is mined with. Bitmain sold it in three performance tiers from 7.3 to 9.4 TH/s, and unlike its Bitcoin models the efficiency differs from tier to tier. Housed in the four-fan Antminer chassis, the KS3 weighs 15.2 kilograms and draws single-phase power between 200 and 240 volts.
Performance tiers of the Antminer KS3
- KS3 7.3 TH/s at 3,188 watts (BTM-KS3-73TH)
- KS3 8.3 TH/s at 3,188 watts (BTM-KS3-83TH)
- KS3 9.4 TH/s at 3,500 watts (BTM-KS3-94TH)
On the KS3 the efficiency does not carry across the tiers: the 9.4 TH/s tier reaches 372 joules per terahash, the 8.3 tier 384 and the 7.3 tier 437, because the smallest tier draws the same power for less hashrate. Bitmain allows itself a tolerance of ten percent on power draw and efficiency, twice as much as on the Bitcoin models of the S19 and S21 series. Anyone sizing the breakers tightly should therefore plan for up to 3,850 watts on the top tier.
Design, power connection and cooling of the KS3
Including the built-in power supply, the chassis is 430 × 195.5 × 290 mm; in its shipping carton the miner measures 570 × 316 × 430 mm and weighs 16.9 kilograms. At around 75 dB it is as loud as the Bitcoin machines of the same generation; it has no place in an office or a flat and needs a site where the noise bothers nobody. Bitmain rates it for operation between 0 and 40 degrees Celsius and for storage between minus 20 and 70 degrees at 10 to 90 percent humidity. The 3,188 to 3,500 watts leave the unit almost entirely as warm exhaust air.
The KS3 requires 200 to 240 volts at 47 to 63 hertz. The up to 20 amps are split across two power cords (IEC C13 connectors) of 10 amps each, and both must be connected. The link to the pool runs over RJ45 at 10/100 Mbit.
Out of the box the KS3 runs with Secure Boot enabled and without root access, which Bitmain says it introduced against firmware viruses. Custom firmware nevertheless exists for the KS3, from NiceHash for the 9.4 and 8.3 TH/s tiers, but only with an additional plug-in card on the control board, the CV Cracker Card, which we stock as an accessory, and only on units whose Bitmain firmware predates April 2024. NiceHash charges a developer fee of one to four percent of the hashrate depending on the overclock. Braiins OS and Vnish do not support the KS3. If you want it, we do both: we fit the Cracker Card and flash the NiceHash firmware before shipping, the service costs 29.90 euros net per unit plus the card, and it is available only for machines you run yourself, not for our hosting. Third-party firmware ends the warranty, Bitmain's as well as ours.
Comparison with the successor generation of the KS3
The KS3 has no predecessor; it was Bitmain's entry into Kaspa mining. In March 2024 the Antminer KS5 Pro followed, and since May 2025 the Antminer KS7 has been on the market as the third generation. The machines side by side:
- Antminer KS3: 372 to 437 J/TH (7.3 to 9.4 TH/s at 3,188 to 3,500 W)
- Antminer KS5 Pro: 150 J/TH (21 TH/s at 3,150 W)
- Antminer KS7: 77 J/TH (36 to 45 TH/s at 2,772 to 3,465 W)
The KS5 Pro delivers more than twice the hashrate while drawing less power than the top KS3 tier, so per terahash it needs only around 40 percent of the energy. One KS5 Pro therefore replaces a good two 9.4 TH/s KS3 units on a single power connection. The KS7 halves the energy per terahash once more: its 40 TH/s tier does the work of a good four KS3 units at 3,080 watts, less power than a single one of them draws. Where the KS3 ranks today in our range by daily revenue is listed in the miner comparison.
Verdict: Kaspa mining with the Antminer KS3
The KS3 ran for us and for our customers without anything much to report, and there is little more to say about its day-to-day behaviour. What hurt it was not the hardware but the pace of Kaspa development: with the KS5 Pro half a year later its efficiency was already outdated. Against the Iceriver KS3M we recommended it to customers for its higher hashrate and for the better spare-parts situation at Bitmain.
In mixed Kaspa fleets the iBeLink machines failed far more often than the KS3. When something did happen on a KS3 it was a hashboard, and in one case merely a drop in hashrate from 8.2 to 5.5 TH/s that a restart cured. Warranty handling through Bitmain, however, took a long time on the KS3, sometimes several months per board.
The Antminer KS3 is a first-generation Kaspa machine that the KS5 Pro has left far behind on efficiency. Whether it still pays its way at your site depends on the electricity price, the Kaspa price and the network hashrate, and you can work that out with our Kaspa mining calculator. The current Kaspa network hashrate and the Kaspa mining pools with share and fees are shown live in the cockpit.
