Custom Turbo loaders use timings defined by the duplicator, and those can be really faster than the usual amstrad speed write 0 or 1 scheme.
A game like Bad Cat from Rainbow Arts use an average 3500 bauds speed for example.
Note: those protections systems are actually using custom turbo blocks and don't need a specific encoder, and are actually sub-parts of the custom turbo loader family:
- Spectrum (loader)
- Gremlin Dot Loader
- Cassys Loader
- Hexagon Loader
- Hewson Counter Loader