Sealevel is Solana’s parallel smart contract execution engine, enabling simultaneous processing of thousands of transactions. Unlike Ethereum’s single-threaded model, Sealevel breaks transactions into smaller, non-conflicting tasks and executes them concurrently across GPU cores. This massively boosts throughput while keeping fees low.

Turbine is Solana’s block propagation protocol, inspired by BitTorrent. It splits data into smaller packets and distributes them across the network in a tree-like structure, reducing bandwidth strain. This allows Solana to handle high transaction volumes without bottlenecks, even with global validator participation.

How They Improve Scalability
Parallel Processing (Sealevel):

Enables 50,000+ TPS by executing non-overlapping transactions in parallel (e.g., two unrelated NFT trades won’t queue).

Reduces latency, as contracts don’t wait for linear validation.

Efficient Data Sharing (Turbine):

Solves the "blockchain bandwidth problem" by streaming data in chunks, preventing validator overload.

Ensures fast synchronisation even with low-bandwidth nodes.

Together, Sealevel and Turbine let Solana scale horizontally while maintaining decentralisation, key to its high-speed, low-cost performance. Future upgrades (like Firedancer) aim to further optimise these systems.