Depending on the GC and what the particular definition of "performance" is for your use case (Memory usage? Throughput? Latency? ...), they don't cause a hit. I

Depending on the GC and what the particular definition of "performance" is for your use case (Memory usage? Throughput? Latency? ...), they don't cause a hit. It depends. For instance, if you never hit the GC memory limit in D, it's faster than manually managing memory since you never free it.