This is somewhat of a known “issue”. See Incremental compilation exploration for some related discussion on why its a bit of a problematic thing to solve.
But it’s also relative to your hardware, as its pretty darn quick for me. I know the compiler really likes having fast single core perf, which can have a big impact like you’re seeing. So really comes down to what your system is 
.
| Command | Mean [ms] | Min [ms] | Max [ms] | Relative |
|---|---|---|---|---|
crystal test.cr |
540.5 ± 21.8 | 511.7 | 577.7 | 1.00 |
Related: CPU Compile Speed Benchmarks