blockchain//sync

Sync is the process by which a blockchain node rebuilds the current state of the chain from its blocks, and the mode chosen for it decides how long a node takes to start, how much it stores and how much it must trust others. A full sync downloads all blocks from genesis and re-executes every transaction, which takes days to weeks for Mainnet; it is slow because verification is CPU-bound, with millions of transactions re-executed to rebuild the current state.

Sync is the process by which a blockchain node rebuilds the current state of the chain from its blocks, and the mode chosen for it decides how long a node takes to start, how much it stores and how much it must trust others. A full sync downloads all blocks from genesis and re-executes every transaction, which takes days to weeks for Mainnet; it is slow because verification is CPU-bound, with millions of transactions re-executed to rebuild the current state.

An archive sync is even slower and larger, because it stores the full state after every block, not just the latest. Light clients (like Metamask) skip all this: they trust an already-synced RPC node for instant access.