Isolated Rollups (e.g., Arbitrum Nova, zkSync Era) provide dedicated execution environments. This architecture excels at performance predictability because an app's performance is insulated from unrelated network activity. For example, during the 2023 meme coin frenzy on Ethereum L1, apps on isolated rollups maintained stable transaction fees and sub-2-second finality, while shared environments saw significant volatility. This makes them ideal for high-frequency DeFi protocols like perpetual exchanges (e.g., GMX on Arbitrum) that require consistent latency.
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Comparisons
Isolated Rollups vs Shared Rollups: Congestion
A technical comparison of isolated and shared rollup architectures, focusing on how each model handles network congestion, its impact on performance and cost, and the trade-offs for protocol architects and CTOs.
Chainscore © 2026
introduction
THE ANALYSIS
Introduction: The Congestion Isolation Problem
How two leading scaling architectures handle network traffic and its impact on performance and cost.
Shared Rollups (e.g., Optimism's Superchain, Polygon CDK chains) take a different approach by creating a network of interoperable chains that share a common sequencing layer and security model. This results in a trade-off: while they can experience correlated congestion during cross-chain messaging spikes, they enable native, low-latency interoperability and shared liquidity. A surge on one chain can be mitigated by routing transactions to a quieter sibling chain within the ecosystem.
The key trade-off: If your priority is guaranteed, isolated performance and cost stability for a single, high-throughput application, choose an Isolated Rollup. If you prioritize native composability and liquidity sharing across a suite of applications or anticipate building a multi-chain ecosystem, a Shared Rollup framework is the superior choice. The decision hinges on whether you value predictable isolation or interconnected flexibility.
tldr-summary
Isolated vs. Shared Rollups
TL;DR: Key Differentiators on Congestion
How each architecture handles network traffic and its impact on performance and cost.
01
Isolated Rollups: Predictable Performance
Guaranteed block space: Each rollup (e.g., an app-specific Arbitrum Orbit chain, a zkSync Hyperchain) has its own dedicated sequencer and block production. Congestion from a high-volume NFT mint on another chain (like Blast) does not impact your chain's TPS or latency. This is critical for high-frequency DeFi protocols like dYdX v4 or perpetual swaps requiring sub-second finality.
02
Isolated Rollups: Tailored Fee Markets
Independent gas pricing: Fee spikes are contained within the application's ecosystem. A gaming app on an Immutable zkEVM chain can maintain stable, low transaction fees even if gas on the shared Ethereum L1 or a general-purpose rollup like Base surges. This enables predictable operational costs for Web3 games and enterprise applications with known user volumes.
03
Shared Rollups: Network Effects & Liquidity
Unified liquidity pool: All applications on a shared rollup (e.g., Arbitrum One, Optimism, zkSync Era) share the same state and native asset for gas. This creates deep, composable liquidity (e.g., a swap on Uniswap directly funding an NFT purchase on OpenSea). Congestion is the trade-off for maximum composability, vital for DeFi ecosystems and social apps like Friend.tech that thrive on interconnectedness.
04
Shared Rollups: Congestion Spillover Risk
Contested block space: A viral event on one app (e.g., a major token launch) can saturate the shared sequencer, causing gas auctions and failed transactions for all other apps on the chain. This was observed during the Arbitrum Odyssey NFT mint and early Optimism airdrops. Teams building mission-critical infrastructure (oracles, bridges) must design for these unpredictable latency spikes.
HEAD-TO-HEAD COMPARISON
Isolated Rollups vs Shared Rollups: Congestion Comparison
Direct comparison of congestion-related performance and design trade-offs.
| Metric / Feature | Isolated Rollups (e.g., Arbitrum, Optimism) | Shared Rollups (e.g., zkSync Era, Starknet) |
|---|---|---|
Congestion Impact Scope | App-specific chain | Entire rollup ecosystem |
Peak TPS (Theoretical) | ~4,000 - 40,000 | ~100 - 3,000 |
Gas Fee Volatility | Low (predictable, app-controlled) | High (shared, demand-driven) |
Sequencer Censorship Risk | Low (dedicated sequencer) | High (shared sequencer) |
MEV Extraction Surface | App-specific | Cross-app, network-wide |
Fee Market Design | Independent | Unified, competitive |
pros-cons-a
PROS AND CONS
Isolated vs. Shared Rollups: Congestion Analysis
Key architectural trade-offs for performance isolation and resource efficiency.
01
Isolated Rollup Pro: Predictable Performance
Guaranteed resource isolation: Each rollup has its own execution environment and sequencer, meaning a viral NFT mint on one chain (e.g., Zora) cannot impact the transaction speed or gas fees of another (e.g., a DeFi protocol on Base). This matters for mission-critical applications requiring sub-second finality and stable fee markets, such as high-frequency trading or gaming.
0%
Cross-Chain Congestion Risk
02
Isolated Rollup Con: Inefficient Capital & Liquidity
Fragmented liquidity and security costs: Each rollup must bootstrap its own validator set, liquidity pools (e.g., Uniswap deployments), and bridge capital. This leads to higher operational overhead and capital inefficiency compared to sharing a base layer's security and liquidity pool. Protocols like dYdX v4 face significant upfront costs to establish their own chain's economic security.
03
Shared Rollup Pro: Capital Efficiency & Composability
Unified liquidity and security: All applications (e.g., Aave, Uniswap, NFT markets) share the same state and sequencer on a single rollup like Arbitrum One. This enables native composability and deep, shared liquidity pools, reducing bridging friction. Security costs are amortized across all users, making it cost-effective for early-stage dApps.
$2B+
Shared TVL Efficiency
04
Shared Rollup Con: Contagion Risk
Single point of congestion: A surge in demand for one application (e.g., a memecoin frenzy) can congest the entire shared sequencer, spiking gas fees and delaying transactions for all other dApps on the chain. This was observed on Arbitrum during the ARB airdrop, where network activity crippled performance for unrelated DeFi protocols.
pros-cons-b
Isolated Rollups vs Shared Rollups
Pros and Cons: Congestion Management
How each architectural choice handles network load and contention for block space.
01
Isolated Rollup Pro: Predictable Performance
Guaranteed block space: Your application's performance is unaffected by unrelated protocols. This matters for high-frequency trading (HFT) DEXs like dYdX v3 (on StarkEx) or gaming applications that require consistent, low-latency transaction inclusion.
02
Isolated Rollup Con: Inefficient Resource Utilization
Fixed capacity, variable demand: Blocks can be empty during low activity, wasting allocated L1 security budget. This matters for niche protocols or new deployments that cannot consistently fill blocks, leading to higher per-transaction cost overhead.
03
Shared Rollup Pro: Dynamic Efficiency
Optimized block space usage: A single sequencer (e.g., Arbitrum One, Optimism Mainnet) batches transactions from thousands of contracts, maximizing L1 data compression. This matters for DeFi ecosystems where composability between protocols like Uniswap, Aave, and Compound is critical and demand fluctuates.
04
Shared Rollup Con: Contention & Fee Volatility
Competitive fee market: High demand from a popular NFT mint or token launch (e.g., a major launch on Blast) can congest the shared sequencer, spiking fees for all other applications. This matters for user experience in mainstream applications where predictable, low cost is a requirement.
ISOLATED ROLLUPS VS SHARED ROLLUPS
Performance and Cost Under Load
Direct comparison of throughput, cost, and reliability metrics during network congestion.
| Metric | Isolated Rollups (e.g., Arbitrum, Optimism) | Shared Rollups (e.g., zkSync Era, Starknet) |
|---|---|---|
Performance Isolation | ||
Peak TPS (Sustained) | 4,000+ | 100+ |
Cost During Congestion | Stable | Spikes with L1 gas |
Sequencer Downtime Impact | Local to chain | Cross-chain (if shared) |
Time to Finality (L1) | ~12 min | ~12 min |
Proposer/Prover Competition |
CHOOSE YOUR PRIORITY
Decision Framework: When to Choose Which
Isolated Rollups for DeFi
Verdict: Choose for High-Value, Complex Applications. Strengths: Congestion isolation is critical for protocols like dYdX v4 (on its own rollup) or Aave-specific chains. Your application's performance is decoupled from unrelated network activity, guaranteeing predictable latency for liquidations, oracle updates, and arbitrage. This is essential for perpetual DEXs, money markets, and sophisticated derivatives where a single block of delay can mean insolvency.
Shared Rollups for DeFi
Verdict: Choose for Composable, General-Purpose Ecosystems. Strengths: Shared sequencing on networks like Arbitrum One and Optimism enables atomic composability—a flash loan on Aave can swap on Uniswap and mint an NFT in a single transaction. While subject to shared congestion, the high throughput (e.g., Arbitrum's 40k+ TPS potential) and deep liquidity pools (e.g., over $18B TVL on Arbitrum) often outweigh the risk for most DeFi primitives. The EVM-equivalent environment lowers integration costs.
verdict
THE ANALYSIS
Final Verdict and Strategic Recommendation
Choosing between isolated and shared rollups is a strategic decision based on your application's tolerance for external congestion versus its need for native composability and security.
Isolated Rollups (e.g., Arbitrum Nova, zkSync Era) excel at predictable performance and cost isolation because they operate their own dedicated sequencer and data availability layer. For example, during periods of high activity on Optimism, an app on a separate Arbitrum chain would not see its gas fees spike, maintaining sub-$0.01 transaction costs while others congest. This architecture provides a sovereign environment where an application's performance is decoupled from the broader ecosystem's traffic.
Shared Rollups (e.g., Optimism Superchain, Arbitrum Orbit chains using AnyTrust) take a different approach by leveraging a shared sequencing and data availability layer. This results in a powerful trade-off: enhanced native composability and shared security at the potential cost of being affected by 'noisy neighbor' congestion. A surge in activity on one app within the Superchain can temporarily increase base fees for all chains in the collective, but it enables atomic cross-chain transactions and a unified liquidity pool that isolated chains cannot match.
The key trade-off is sovereignty versus synergy. If your priority is performance isolation and predictable economics for a high-throughput application like a gaming or social protocol, choose an Isolated Rollup. If you prioritize deep, trust-minimized composability and are building a DeFi protocol that must interact atomically with other applications, a Shared Rollup within a collective like the OP Stack or Arbitrum Orbit is the superior strategic choice. Your decision hinges on whether congestion risk is an existential threat or an acceptable cost for ecosystem integration.
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