Consensus
Unlike Ethereum, Klaytn runs a variant of PBFT algorithm to make consensus. Running BFT has some pros and cons.
Pros: faster, efficient consensus
Cons: network has to be synchronized
Obviously, if your network has to be synced, it is difficult to achieve decentralized consensus. Since general BFT algorithms require at least two-third of all nodes to be involved to come to an agreement, forming a large network will suffer from significant network overhead.
Klaytn uses a workaround: instead of requiring all nodes to participate consensus, only a random subset of nodes is chosen to run consensus. How do we pick ‘random’ though? There is something called Verifiable Random Function (VRF) which is very handy when you need to generate a random value that can be verified cryptographically. For every block generation, Klaytn picks a random number using VRF, identify a group of nodes — called a committee — to run BFT. The size of a committee is sufficiently small to output high TPS. Currently, Klaytn handles more than 4,000 transactions per second with 50 GC nodes.
You can find more details from here.