What Solana’s Alpenglow Switch Actually Changes at Slot 459,653,000

For about 400 milliseconds this afternoon, Solana will stop landing user transactions. That isn't a failure. It's the scheduled handoff between two consensus systems, and it's probably the only "400 ms" figure that matters today. Many people heading into the Alpenglow launch still treat 400 ms block times and 12.8-second finality as the bar to beat. Those are the old chain's numbers. They describe TowerBFT, the system Alpenglow is replacing, so Alpenglow shouldn't be checked against them. If you go through Solana's own documentation, you'll find the right benchmarks before the first post-launch numbers arrive.