Private vs. Public Blockchain: Solving the Speed Issue

I’ve spent the last decade watching developers pull their hair out over blockchain speeds. I’ve sat in rooms where “enterprise-grade” private chains crashed during a simple stress test. I’ve also waited forty minutes for a “fast” public chain to confirm a single transaction while the gas fees ate my profit.

The debate used to be simple: Public is for the people, private is for the suits. But in 2026, that line has blurred. The real fight isn’t about philosophy anymore. It’s about throughput. It’s about how we stop these ledgers from becoming digital traffic jams. If a blockchain can’t handle 50,000 transactions per second (TPS), it’s just a slow, expensive database. Here is the reality of the speed war.

The Speed Gap: Why Your Public Chain Feels Like Dial-Up

Public blockchains are permissionless. Anyone with a laptop can join. That is their greatest strength and their biggest bottleneck. Think of it like a town hall meeting where ten thousand people have a microphone. If everyone has to verify every word spoken, the meeting takes forever. That is the propagation delay.

In a public network like Ethereum or Bitcoin, nodes are scattered across the globe. When a transaction happens, it has to travel across the internet, hit thousands of computers, and get added to a block. Then, those computers have to reach a consensus. This takes time. Bitcoin gives you about 7 TPS. Ethereum, even after its upgrades, handles around 15-30 on its main layer. Compared to Visa’s 65,000 TPS, these numbers are a joke.

I saw a startup try to run a high-frequency trading bot on a public chain last year. They went bust in three hours. The latency—the time between sending a command and it being finalized—was too high. In the public world, you aren’t just paying for security; you are paying a “slowness tax.”

Public Blockchains: The Cost of Freedom

Why do we put up with it? Because public chains offer censorship resistance. No one can turn off the network. But that freedom comes with the Scalability Trilemma. This is a rule coined by Vitalik Buterin. It says you can only pick two: Security, Decentralization, or Scalability.

The Scalability Trilemma: You Can’t Have It All

If you want it to be fast (Scalable) and Decentralized, you lose Security. If you want it Secure and Decentralized, it’s going to be slow. Most public chains choose Security and Decentralization. They use Proof of Stake (PoS) or Proof of Work (PoW) to keep the bad guys out. But these mechanisms require heavy communication between nodes.

Solana: A Race for Throughput

Solana tried to break the trilemma using Proof of History (PoH). It’s basically a digital clock that lets nodes agree on time without talking to each other first. It’s fast—hitting 50,000 TPS in lab settings. But I’ve seen it go dark. When you push that much data through a network, the hardware requirements skyrocket. If only a few people can afford the servers to run the network, is it still decentralized? Probably not.

Private Blockchains: Built for the Fast Lane

Private or “Permissioned” blockchains like Hyperledger Fabric and R3 Corda don’t have this problem. They don’t let just anyone in. You need an invite. Because the actors are known and vetted, you don’t need a massive, wasteful consensus dance.

Why Hyperledger and Corda Move Faster

In a private setup, you use Crash Fault Tolerance (CFT) or Byzantine Fault Tolerance (BFT) algorithms like Raft or PBFT. These are much leaner. Instead of ten thousand nodes, you might have ten. They can reach a decision in milliseconds.

I worked with a logistics firm using Hyperledger to track shipping containers. They didn’t need a million nodes. They just needed the port, the shipping line, and the bank to agree. Their finality—the moment a transaction is set in stone—was nearly instant. There was no “waiting for six confirmations.”

The Trade-off: Security vs. Control

The catch is simple: if the person running the private chain decides to delete your data, they can. It’s a “walled garden.” For a bank, that’s a feature. For a crypto-enthusiast, it’s a nightmare. Private chains solve the speed issue by reintroducing centralization.

Breaking Down the Numbers: TPS Realities in 2026

Don’t believe the marketing slides. Most TPS numbers are “peak” theoretical speeds, not “sustained” real-world speeds.

• Bitcoin: 7 TPS. Great for gold, terrible for coffee.
• Ethereum (Layer 1): 20-30 TPS. The “World Computer” is still a bit sluggish.
• Hyperledger Fabric: 3,000+ TPS. Depends on your hardware.
• Solana: 2,000 – 50,000 TPS. High variance, frequent congestion.
• Rollups (Layer 2): 10,000+ TPS. This is where the public world is catching up.

The real metric to watch isn’t TPS; it’s Time to Finality (TTF). If a chain says it does 100k TPS but takes ten minutes to confirm, it’s useless for retail. Private chains usually win on TTF because they don’t have to worry about “re-orgs” or forks.

Solving the Speed Issue: The New Tech Stack

We are moving away from the “Monolithic” era. In the old days, one blockchain did everything: execution, settlement, and data availability. That’s why they were slow. The fix is Modular Blockchains.

Layer 2 Rollups and ZK-Proofs

Public chains are now using Layer 2s (L2s). Think of an L2 as a side street off a main highway. You do all the fast driving (transactions) on the side-street, bundle them into a single package, and then post that package to the main highway (Layer 1).

Zero-Knowledge Proofs (ZK-Proofs) are the magic here. They allow one party to prove a transaction is valid without revealing the data. This makes ZK-Rollups incredibly fast and private, even on a public chain. It’s the best of both worlds. I’m seeing massive adoption of ZK-tech in 2026 because it finally fixes the privacy-speed-security triangle.

Sharding: Breaking the Database

Sharding is like opening more checkout lanes at a grocery store. Instead of one long line, you split the blockchain into “shards.” Each shard handles its own transactions. Ethereum’s roadmap relies heavily on Danksharding to lower data costs and boost speed. It’s complex, and it’s taken years to build, but it’s the only way a public chain scales to millions of users.

Parallel Execution: Doing Everything at Once

Most blockchains are “serial.” They process one transaction at a time. If Alice sends money to Bob, and Charlie sends money to Dave, the chain goes Alice first, then Charlie. Parallel execution (used by chains like Aptos and Sui) lets the network process unrelated transactions at the same time. It’s like having a multi-core processor instead of an old single-core chip.

The Hybrid Approach: The Best of Both Worlds?

I’m seeing a lot of companies give up on the “Public vs. Private” binary. They are building Hybrid Blockchains.

A company might keep its sensitive data on a private sidechain for speed and privacy. Every hour, they “anchor” a hash of that data onto a public chain like Ethereum. This gives them the speed of a private network but the “immutability” of a public one. If the private server gets hacked, the public record proves what the data *should* have been. This is the Auditability play that banks love.

Hardware Matters: The Rise of Blockchain Chips

We’ve reached the limit of what software can do. In 2026, the speed issue is being solved by silicon. We are seeing the rise of ZK-ASICs and FPGAs specifically designed to generate cryptographic proofs.

In the past, generating a ZK-proof took a lot of CPU power. It was slow. Now, dedicated hardware can do it in milliseconds. This is a game-changer for throughput. Just like GPUs changed gaming and AI, these blockchain chips are making “instant” public transactions a reality. If you aren’t looking at the hardware layer, you’re missing half the story.

Real-World Use Cases: Speed in Action

Supply Chain and Logistics

In a global supply chain, you need speed. If a ship is waiting at a dock, you can’t wait twenty minutes for a block to confirm. Private chains dominate here. IBM Food Trust uses a permissioned model to track mangoes from farm to store in seconds. They don’t need decentralization; they need a shared source of truth that moves at the speed of business.

Central Bank Digital Currencies (CBDCs)

Governments are building CBDCs. Do they use public chains? Never. They use highly customized, private versions of Quorum or Hyperledger. They need to process millions of retail transactions per second. They also need to be able to “undo” a transaction if there is fraud. You can’t do that on a public chain. Speed and Governance are the priorities here.

DeFi and High-Frequency Trading

This is the public chain’s home turf. Decentralized Finance (DeFi) needs to be permissionless. To solve the speed issue, these apps are moving to AppChains—blockchains dedicated to a single application. By having their own space, they don’t have to compete with NFT mints or meme coins for bandwidth.

The Verdict: Which One Should You Build On?

Don’t listen to the maximalists. There is no “one chain to rule them all.”

If you are building a system where privacy and raw speed are the only things that matter—and you trust your partners—go Private. It’s cheaper, faster, and easier to manage. It’s basically a shared database with an audit trail.

If you are building something that needs to be global, unstoppable, and transparent, you have to go Public. But don’t build on the main layer. Use an L2 or a Modular stack. Use ZK-proofs to keep your data fast and lean.

The “Speed Issue” isn’t a single problem. It’s a trade-off. In 2026, we finally have the tools to choose exactly how much speed we want to buy and what we are willing to give up to get it. The gap is closing, but the choice still matters.