What's much more important for good performance is memory layout and good use of CPU caches. And in this area managed languages struggle a lot. For instance, every object in Java has 16 bytes of overhead for an object header (on 64-bit openjdk jvm). Or you can't organize objects in a flat array. Or there are some guarantees about memory zeroing which often lead to needless memory writes. Or you have to live with GC, which often wastes a lot additional memory and regularly brings unused but reachable memory to caches. Project Valhalla is going to improve some of these limitations hopefully some day, but don't expect the level of C, C++ or Rust performance.