Looking at their benchmarks -- specifically, in C++ -- I immediately see a coding error that probably makes the protobufs version run half as fast as it should.

Looking at their benchmarks -- specifically, in C++ -- I immediately see a coding error that probably makes the protobufs version run half as fast as it should. Namely, they make multiple redundant calls to message.ByteSize(). ByteSize() is not free -- it has to walk the whole message to compute the size, doing many of the same expensive branches that would be needed when actually serializing. Had they profiled their benchmark, they would have noticed this. This is just from one minute of looking. There are probably more problems. Unfortunately, I find this is typical of benchmarks that claim something is massively faster than Protobufs. Admittedly, this may be indicative of the Protobuf interface being unintuitive. Not that I doubt that SBE is faster; the design should obviously make it so. But it's probably not 25x faster. Update: Bug filed: https://github.com/real-logic/simple-binary-encoding/issues/128 https://github.com/real-logic/simple-binary-encoding/issues/...