It would appear so:

```scala
scala> val th = new ichi.bench.Thyme

scala> val items = Array.tabulate(10000) { i => (i, i) }

scala> def a(items: Seq[(Int, Int)]): Map[Int, Int] = Map(items: _*)

scala> def b(items: Seq[(Int, Int)]): Map[Int, Int] = { val map = new mutable.HashMap[Int, Int]; map.sizeHint(items.size); items.foreach { case (k, v) => map.put(k, v) }; map }

scala> th.pbench { a(items) }
Benchmark (2540 calls in 7.554 s)
  Time:    2.352 ms   95% CI 2.260 ms - 2.443 ms   (n=20)
  Garbage: 560.2 us   (n=344 sweeps measured)

scala> th.pbench { b(items) }
Benchmark (5100 calls in 5.399 s)
  Time:    961.5 us   95% CI 919.1 us - 1.004 ms   (n=20)
  Garbage: 83.59 us   (n=101 sweeps measured)
```

Thyme is great for benchmarking this kind of stuff (might be useful to use Thyme to compare the AppendOnlyHashMap vs. scala.collection.mutable.OpenHashMap too).

https://github.com/Ichoran/thyme