diff --git a/akka-actor/src/main/scala/akka/dispatch/AbstractDispatcher.scala b/akka-actor/src/main/scala/akka/dispatch/AbstractDispatcher.scala
index 12c8c89d25..29be04fe40 100644
--- a/akka-actor/src/main/scala/akka/dispatch/AbstractDispatcher.scala
+++ b/akka-actor/src/main/scala/akka/dispatch/AbstractDispatcher.scala
@@ -282,8 +282,6 @@ abstract class MessageDispatcher(val prerequisites: DispatcherPrerequisites) ext
 
   @inline
   protected[akka] final val isThroughputDeadlineTimeDefined = throughputDeadlineTime.toMillis > 0
-  @inline
-  protected[akka] final val isThroughputDefined = throughput > 1
 
   protected[akka] def executeTask(invocation: TaskInvocation)
 
diff --git a/akka-actor/src/main/scala/akka/dispatch/Mailbox.scala b/akka-actor/src/main/scala/akka/dispatch/Mailbox.scala
index 195f77ee94..e0bda0c41e 100644
--- a/akka-actor/src/main/scala/akka/dispatch/Mailbox.scala
+++ b/akka-actor/src/main/scala/akka/dispatch/Mailbox.scala
@@ -172,19 +172,18 @@ private[akka] abstract class Mailbox(val actor: ActorCell) extends MessageQueue
 
   /**
    * Process the messages in the mailbox
-   *
-   * @return true if the processing finished before the mailbox was empty, due to the throughput constraint
    */
-  private final def processMailbox(): Unit = if (dispatcher.isThroughputDefined) process(dispatcher.throughput) else process(1)
-
-  @tailrec private final def process(left: Int, deadlineNs: Long = if (dispatcher.isThroughputDeadlineTimeDefined) System.nanoTime + dispatcher.throughputDeadlineTime.toNanos else 0l): Unit =
-    if ((left > 0) && (shouldProcessMessage) && (!dispatcher.isThroughputDeadlineTimeDefined || System.nanoTime < deadlineNs)) {
+  @tailrec private final def processMailbox(
+    left: Int = java.lang.Math.min(dispatcher.throughput, 1),
+    deadlineNs: Long = if (dispatcher.isThroughputDeadlineTimeDefined) System.nanoTime + dispatcher.throughputDeadlineTime.toNanos else 0l): Unit =
+    if (shouldProcessMessage) {
       val next = dequeue()
       if (next ne null) {
         if (Mailbox.debug) println(actor.self + " processing message " + next)
         actor invoke next
         processAllSystemMessages()
-        process(left - 1, deadlineNs)
+        if ((left > 1) && (!dispatcher.isThroughputDeadlineTimeDefined || System.nanoTime < deadlineNs))
+          processMailbox(left - 1, deadlineNs)
       }
     }