Currently, Solana is producing 400 millisecond block times, but this speed will continue to improve as the hardware that validators use improves. "The speed of light is how fast we can make this network go," says Solana's founder Anatoly Yakovenko.
This high-performance speed is possible as the validators follow a calculation based on data already on the blockchain to determine a schedule for adding blocks. Instead of validators having to communicate with each other, the calculation determines the next block leader, allowing the network to process new blocks much faster than other blockchains.
Importantly, blocks from validators are then only accepted if they follow the schedule, which is enforced with their proof-of-history consensus mechanism.