I have a moderately large C++ project based on CMake. When opened in QtCreator with Clang code model enabled, it consumes around 590 MiB of RAM (after the initial parsing completes). However, as I start typing the code, CPU gets constantly loaded (I suppose, 1 or 2 threads) and memory consumption quickly raises to ~1.5 GiB. I didn't spend too much time editing the code, so this may not be the end.

I think 590 MiB is acceptable, but 1.5 GiB is too much. Using the builtin QtCreator code model, opening the project consumes around 306 MiB, and further on it usually doesn't grow beyond ~700 MiB after several hours of coding.