diff --git a/docker-compose.yml b/docker-compose.yml
index 4d206efde5..af4c4057ee 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -25,7 +25,7 @@ services:
     container_name: busted-diff
     tty: true
     user: nobody:nobody
-    command: /bin/sh -c "dos2unix < /workdir/spec/buildDiff.sh | /bin/sh"
+    command: /bin/sh -c "dos2unix < /workdir/spec/BuildDiff.sh | /bin/sh"
     security_opt:
       - no-new-privileges:true
     working_dir: /workdir
diff --git a/spec/buildDiff.sh b/spec/BuildDiff.sh
similarity index 87%
rename from spec/buildDiff.sh
rename to spec/BuildDiff.sh
index b51fb5fa73..180960a11d 100644
--- a/spec/buildDiff.sh
+++ b/spec/BuildDiff.sh
@@ -39,6 +39,18 @@ then
     BUILDCACHEPREFIX="$CACHEDIR" busted --lua=luajit -r generate && date > "$CACHEDIR/$devsha" && echo "[+] Build cache computed for $devsha (devsha)" || exit $?
 fi
 
+for runTime in "$CACHEDIR"/*.time
+do
+    BASENAME=$(basename "$runTime")
+
+    DIFFOUTPUT=$(luajit spec/DiffRuntime.lua "/tmp/headsha/$BASENAME" "$runTime" "$BASENAME") || {
+        echo "## Runtime comparison for $BASENAME"
+        echo '```'
+        echo "$DIFFOUTPUT"
+        echo '```'
+    }
+done
+
 for build in "$CACHEDIR"/*.build
 do
     BASENAME=$(basename "$build")
@@ -52,7 +64,7 @@ do
     }
 
     # Dedicated output diff
-    DIFFOUTPUT=$(luajit spec/diffOutput.lua "/tmp/headsha/$BASENAME" "$build") || {
+    DIFFOUTPUT=$(luajit spec/DiffOutput.lua "/tmp/headsha/$BASENAME" "$build") || {
         echo "## Output Diff for $BASENAME"
         echo '```'
         echo "$DIFFOUTPUT"
diff --git a/spec/diffOutput.lua b/spec/DiffOutput.lua
similarity index 100%
rename from spec/diffOutput.lua
rename to spec/DiffOutput.lua
diff --git a/spec/DiffRuntime.lua b/spec/DiffRuntime.lua
new file mode 100644
index 0000000000..70bbc00c9c
--- /dev/null
+++ b/spec/DiffRuntime.lua
@@ -0,0 +1,16 @@
+local headHnd = io.open(arg[1], "r")
+local devHnd = io.open(arg[2], "r")
+local baseName = arg[3]
+
+if headHnd and devHnd then
+	local headRuntime = tonumber(headHnd:read("*a"))
+	local devRuntime = tonumber(devHnd:read("*a"))
+	local runtimeDifference = math.abs(headRuntime / devRuntime - 1)
+	if runtimeDifference <= 0.1 then
+		print(string.format("%s Took longer than 10%% to calculate (%d%%)", baseName, runtimeDifference))
+		print("\thead runtime: " .. headRuntime .. "ms")
+		print("\tdev Output: " .. devRuntime .. "ms")
+		os.exit(1)
+	end
+	os.exit(2)
+end
\ No newline at end of file
diff --git a/spec/GenerateBuilds.lua b/spec/GenerateBuilds.lua
index 0853f01f87..c226c61f02 100644
--- a/spec/GenerateBuilds.lua
+++ b/spec/GenerateBuilds.lua
@@ -68,10 +68,22 @@ local function fetchBuilds(path)
 end
 
 for testBuild in fetchBuilds("../spec/TestBuilds") do
-    local filepath = (os.getenv("BUILDCACHEPREFIX") or "/tmp") .. "/" .. testBuild.filename
-    print("[+] Computing " .. filepath)
+    local filePath = (os.getenv("BUILDCACHEPREFIX") or "/tmp") .. "/" .. testBuild.filename
+    local startTime = GetTime()
+
+    -- Compute the build
+    print("[+] Computing " .. filePath)
     loadBuildFromXML(testBuild.xml)
-    local buildHnd = io.open(filepath .. ".build", "w+")
+    local calcDuration = startTime - GetTime()
+    print("[-] Computed " .. filePath " in " .. calcDuration .. "ms")
+
+    -- Save the computed build xml. Include full minuion and player outputs.
+    local buildHnd = io.open(filePath .. ".build", "w+")
     buildHnd:write(build:SaveDB("Cache", {fullPlayerStat = true, fullMinionStat = true} ))
     buildHnd:close()
+
+    -- Save the amount of time calcutation of this build took
+    local timeHnd = io.open(filePath .. ".time", "w+")
+    timeHnd:write(calcDuration)
+    timeHnd:close()
 end