diff --git a/src/main/resources/application.conf b/src/main/resources/application.conf
index 955811673..96278a388 100644
--- a/src/main/resources/application.conf
+++ b/src/main/resources/application.conf
@@ -951,7 +951,7 @@ opencomputers {
 
     # The amount of ticks the delay is *reduced* by per tier of the CPU
     # inserted into a switch.
-    relayDelayUpgrade: 1
+    relayDelayUpgrade: 1.5
 
     # This is the size of the queue of a not upgraded switch. Increasing it
     # avoids packets being dropped when many messages are sent in a single
diff --git a/src/main/scala/li/cil/oc/Settings.scala b/src/main/scala/li/cil/oc/Settings.scala
index 65c407689..ae7f7432f 100644
--- a/src/main/scala/li/cil/oc/Settings.scala
+++ b/src/main/scala/li/cil/oc/Settings.scala
@@ -286,7 +286,7 @@ class Settings(val config: Config) {
   val switchDefaultMaxQueueSize = config.getInt("switch.defaultMaxQueueSize") max 1
   val switchQueueSizeUpgrade = config.getInt("switch.queueSizeUpgrade") max 0
   val switchDefaultRelayDelay = config.getInt("switch.defaultRelayDelay") max 1
-  val switchRelayDelayUpgrade = config.getInt("switch.relayDelayUpgrade") max 0
+  val switchRelayDelayUpgrade = config.getDouble("switch.relayDelayUpgrade") max 0
   val switchDefaultRelayAmount = config.getInt("switch.defaultRelayAmount") max 1
   val switchRelayAmountUpgrade = config.getInt("switch.relayAmountUpgrade") max 0
 
@@ -493,6 +493,10 @@ object Settings {
       "power.value.IndustrialCraft2",
       "power.value.Mekanism",
       "power.value.RedstoneFlux"
+    ),
+    // Upgrading to version 1.5.20, changed relay delay default.
+    VersionRange.createFromVersionSpec("[0.0, 1.5.20)") -> Array(
+      "switch.relayDelayUpgrade"
     )
   )
 
diff --git a/src/main/scala/li/cil/oc/common/tileentity/Relay.scala b/src/main/scala/li/cil/oc/common/tileentity/Relay.scala
index b10b10d3e..e906ddfb0 100644
--- a/src/main/scala/li/cil/oc/common/tileentity/Relay.scala
+++ b/src/main/scala/li/cil/oc/common/tileentity/Relay.scala
@@ -199,7 +199,7 @@ class Relay extends traits.SwitchLike with traits.ComponentInventory with traits
   private def updateLimits(slot: Int, stack: ItemStack) {
     Option(Driver.driverFor(stack, getClass)) match {
       case Some(driver) if driver.slot(stack) == Slot.CPU =>
-        relayDelay = math.max(1, relayBaseDelay - ((driver.tier(stack) + 1) * relayDelayPerUpgrade))
+        relayDelay = math.max(1, relayBaseDelay - ((driver.tier(stack) + 1) * relayDelayPerUpgrade).toInt)
       case Some(driver) if driver.slot(stack) == Slot.Memory =>
         relayAmount = math.max(1, relayBaseAmount + (Delegator.subItem(stack) match {
           case Some(ram: item.Memory) => (ram.tier + 1) * relayAmountPerUpgrade
diff --git a/src/main/scala/li/cil/oc/common/tileentity/ServerRack.scala b/src/main/scala/li/cil/oc/common/tileentity/ServerRack.scala
index bbdcd1caa..b5ff9948f 100644
--- a/src/main/scala/li/cil/oc/common/tileentity/ServerRack.scala
+++ b/src/main/scala/li/cil/oc/common/tileentity/ServerRack.scala
@@ -56,7 +56,7 @@ class ServerRack extends traits.PowerAcceptor with traits.Hub with traits.PowerB
   var lastAccess = Array.fill(4)(0L)
 
   val builtInSwitchTier = Settings.get.serverRackSwitchTier
-  relayDelay = math.max(1, relayBaseDelay - (builtInSwitchTier + 1) * relayDelayPerUpgrade)
+  relayDelay = math.max(1, relayBaseDelay - ((builtInSwitchTier + 1) * relayDelayPerUpgrade).toInt)
   relayAmount = math.max(1, relayBaseAmount + (builtInSwitchTier + 1) * relayAmountPerUpgrade)
   maxQueueSize = math.max(1, queueBaseSize + (builtInSwitchTier + 1) * queueSizePerUpgrade)
 
diff --git a/src/main/scala/li/cil/oc/common/tileentity/Switch.scala b/src/main/scala/li/cil/oc/common/tileentity/Switch.scala
index 794893d9a..45f972270 100644
--- a/src/main/scala/li/cil/oc/common/tileentity/Switch.scala
+++ b/src/main/scala/li/cil/oc/common/tileentity/Switch.scala
@@ -61,7 +61,7 @@ class Switch extends traits.SwitchLike with traits.NotAnalyzable with traits.Com
   private def updateLimits(slot: Int, stack: ItemStack) {
     Option(Driver.driverFor(stack, getClass)) match {
       case Some(driver) if driver.slot(stack) == Slot.CPU =>
-        relayDelay = math.max(1, relayBaseDelay - ((driver.tier(stack) + 1) * relayDelayPerUpgrade))
+        relayDelay = math.max(1, relayBaseDelay - ((driver.tier(stack) + 1) * relayDelayPerUpgrade).toInt)
       case Some(driver) if driver.slot(stack) == Slot.Memory =>
         relayAmount = math.max(1, relayBaseAmount + (Delegator.subItem(stack) match {
           case Some(ram: item.Memory) => (ram.tier + 1) * relayAmountPerUpgrade
diff --git a/src/main/scala/li/cil/oc/common/tileentity/traits/Hub.scala b/src/main/scala/li/cil/oc/common/tileentity/traits/Hub.scala
index d17611648..4770c6c70 100644
--- a/src/main/scala/li/cil/oc/common/tileentity/traits/Hub.scala
+++ b/src/main/scala/li/cil/oc/common/tileentity/traits/Hub.scala
@@ -71,7 +71,7 @@ trait Hub extends traits.Environment with SidedEnvironment {
           relayPacket(sourceSide, packet)
         }
         if (queue.nonEmpty) {
-          relayCooldown = relayDelay
+          relayCooldown = relayDelay - 1
         }
       }
       else if (world.getTotalWorldTime % relayDelay == 0) {
@@ -84,7 +84,7 @@ trait Hub extends traits.Environment with SidedEnvironment {
     if (packet.ttl > 0 && queue.size < maxQueueSize) {
       queue += sourceSide -> packet.hop()
       if (relayCooldown < 0) {
-        relayCooldown = relayDelay
+        relayCooldown = relayDelay - 1
       }
       true
     }