https://rchain.coop/What makes RChain unique?
RChain is more than a blockchain. The Rchain infrastructure uses new technology based on industry-proven methods to make it safe, efficient, scalable, and fast. Smart contracts on RChain will be written in Rholang, a language with a semantics that will cause faulty contracts to fail to compile, such as the one in the infamous “DAO Attack.” The RChain blockchain, Rholang language, and the storage component are all being developed together so all the pieces fit together in a way that leads to greater efficiency and fewer possibilities for errors or intentional exploits. Sharding and concurrency built into the RChain platform will lead to greater performance than existing blockchains for applications where scaling and speed are essential.
Greg Meredith has worked closely with Vlad Zamfir and Vitalik Buterin on the Casper proof of stake consensus protocol.
Sharded & Concurrent Blockchain
RChain is being developed as a sharded blockchain. This is quite possibly one of the largest breakthroughs in crypto in recent years. Sharding allows clients to subscribe to selected address spaces without downloading the entire blockchain. This allows for concurrent betting on and committing of blocks that don’t conflict with or relate to each other, which will save large amounts of time and resources, leading to scalability that has not been possible for a blockchain before.
https://steemit.com/beyondbitcoin/@stealthtrader/rchain-vs-blockchain