This article discusses how TimescaleDB (packaged as an extension to PostgreSQL) approaches performance improvements, though it's a bit of an old piece and things have moved on with TimescaleDB too. It gives some good insights though. https://www.timescale.com/blog/timescaledb-vs-6a696248104e/ There are some more recent articles on the blog about performance and benchmarks if you're tantalized by that one.
Transparency: I work for Timescale