Use ScalaBlitz optimize block, to make collection operations faster! Simply import the scala.collection.optimizer package, and take full advantage of it. Eg. this example becomes 2x faster! import scala.collection.optimizer._ def average(x: List[Double]) = optimize { x.sum / x.size } import scala.collection.par._ import Scheduler.Implicits.global (0 until 15000000).toPar.reduce(_ + _) With ScalaBl