Bitcoin’s Hashrate Explosion Fuels Historic Security for Merge-Mined Chains

Bitcoin’s hashrate hit beast mode this week, flexing a record-smashing 1,109 exahash per second (EH/s) as the network cranked its computational biceps harder than ever. Meanwhile, Bitcoin’s hashrate fireworks are lighting up merge mined neighbors too, with Namecoin, Rootstock, and Fractal Bitcoin all hitching a ride on the rocket and scoring monster boosts of their own.

How Merge Mining Has Unleashed 700+ EH/s Power Plays

Thanks to merge mining—aka auxiliary proof-of-work (AuxPoW)— Bitcoin’s hashrate isn’t a one-trick pony. Miners can flex the same computational grind to lock down multiple chains at once, turning their application-specific integrated circuit (ASIC) rigs into multitasking machines.

Recently, Bitcoin has officially stomped into the zettahash per second (ZH/s) era, where today’s miners are collectively pumping out a mind-bending 1,000 EH/s. That tidal wave of hashpower isn’t just bulking up Bitcoin—it’s juicing Namecoin, Rootstock, and Fractal Bitcoin too, as today’s heavyweight mining pools moonlight across these side gigs while flexing their mainnet muscle.

Take Namecoin, the OG altcoin born in 2011—it rides shotgun with Bitcoin through merge mining and has for years. Right now, it’s flexing 732 EH/s, and at block 791037 last week, it cranked out an all-time high of 786.98 EH/s. Clocking in at 786.98 EH/s, Namecoin’s peak hash isn’t just a mere blip—it outmuscles the combined strength of several of today’s top proof-of-work (PoW) networks.

Rootstock (RSK) hashrate at 9:25 a.m. Eastern on Sept. 29, 2025.

Rootstock, a Bitcoin sidechain built for smart contracts with its RBTC token pegged 1:1 to $BTC, is another big winner from Bitcoin’s towering hashrate. Using merge mining, it taps into Bitcoin’s security while miners pocket RSK transaction fees alongside their $BTC rewards. At present, Rootstock is clocking roughly 822.92 EH/s.

In other words, Namecoin is riding on about 69.3% of Bitcoin’s current 1,057 EH/s, while Rootstock is locking down a solid 77.85%—serious hashpower hand-me-downs from the big chain. Fractal Bitcoin (FB) is no slouch either, pulling in 768.91 EH/s from Bitcoin’s overflow.

FB runs on a hybrid setup—merge mined alongside Bitcoin, yet also mined on its own. Framed as a Bitcoin scaling solution, it stacks recursive layers built from Bitcoin Core code, aiming to stretch the chain’s reach without breaking its base.

Altogether, Bitcoin’s march into the zettahash era isn’t just flexing its own dominance—it’s lifting a few ecosystems in its wake. With several networks siphoning off massive portions of that hashrate, merge mining has proven itself more than a technical footnote—it’s a full-blown multiplier of security and scale across multiple PoW networks.