It tends to be. While it does use a GC, it has both bytecode and native AOT compilers. When compiled to native, it's closer in performance to C++ and Rust than to C# or Java. It's a reasonable middle ground in PL design that Nim also tries to occupy. In recent years, OCaml's runtime also shed the GIL, making it a good solution for parallelizable, CPU-bound tasks. As a language, OCaml is one of the most impressive ones (in terms of features and capabilities), yet it still provides strong, practical tooling, good performance, and access to low-level-ish features.

TL;DR: OCaml is usually going to be a bit slower than C++, but faster than Java, while rivaling Rust and Haskell in terms of expressive power.

Caveat: a lot of the power comes from the tooling. Last I checked, syntax extensions were external preprocessors, just with standardized APIs. And you need those extensions for things that are handled by (in-language) macros in Rust (like deriving string representation for a record). Without the tooling, OCaml can get a bit tedious/boilerplate-y. OTOH, after a period of instability and competing solutions, the tooling mostly settled down, and enabling the important parts is often a single line in the config. It's not a situation unique to OCaml, but if you look at the language docs only, you'll miss half of what OCaml development normally offers.