diff --git a/configs/common/Simulation.py b/configs/common/Simulation.py
index 374ff3fc2..e037d0343 100644
--- a/configs/common/Simulation.py
+++ b/configs/common/Simulation.py
@@ -39,6 +39,9 @@ def setCPUClass(options):
     if options.timing:
         TmpClass = TimingSimpleCPU
     elif options.detailed:
+        if not options.caches:
+            print "O3 CPU must be used with caches"
+            sys.exit(1)
         TmpClass = DerivO3CPU
     else:
         TmpClass = AtomicSimpleCPU