diff --git a/tests/configs/pc-simple-atomic.py b/tests/configs/pc-simple-atomic.py
index 94a06ed6f..dba382152 100644
--- a/tests/configs/pc-simple-atomic.py
+++ b/tests/configs/pc-simple-atomic.py
@@ -39,5 +39,5 @@ from m5.objects import *
 from x86_generic import *
 
 root = LinuxX86FSSystemUniprocessor(mem_mode='atomic',
-                                    mem_class=DDR3_1600_x64,
+                                    mem_class=SimpleMemory,
                                     cpu_class=AtomicSimpleCPU).create_root()
diff --git a/tests/configs/realview-simple-atomic-dual.py b/tests/configs/realview-simple-atomic-dual.py
index 0d6b11cf6..32d66f6af 100644
--- a/tests/configs/realview-simple-atomic-dual.py
+++ b/tests/configs/realview-simple-atomic-dual.py
@@ -39,6 +39,6 @@ from m5.objects import *
 from arm_generic import *
 
 root = LinuxArmFSSystem(mem_mode='atomic',
-                        mem_class=DDR3_1600_x64,
+                        mem_class=SimpleMemory,
                         cpu_class=AtomicSimpleCPU,
                         num_cpus=2).create_root()
diff --git a/tests/configs/realview-simple-atomic.py b/tests/configs/realview-simple-atomic.py
index a440de291..b51954879 100644
--- a/tests/configs/realview-simple-atomic.py
+++ b/tests/configs/realview-simple-atomic.py
@@ -39,6 +39,6 @@ from m5.objects import *
 from arm_generic import *
 
 root = LinuxArmFSSystemUniprocessor(mem_mode='atomic',
-                                    mem_class=DDR3_1600_x64,
+                                    mem_class=SimpleMemory,
                                     cpu_class=AtomicSimpleCPU).create_root()
 
diff --git a/tests/configs/realview-switcheroo-atomic.py b/tests/configs/realview-switcheroo-atomic.py
index bab11ebe6..abcfb5179 100644
--- a/tests/configs/realview-switcheroo-atomic.py
+++ b/tests/configs/realview-switcheroo-atomic.py
@@ -40,7 +40,7 @@ from arm_generic import *
 import switcheroo
 
 root = LinuxArmFSSwitcheroo(
-    mem_class=DDR3_1600_x64,
+    mem_class=SimpleMemory,
     cpu_classes=(AtomicSimpleCPU, AtomicSimpleCPU)
     ).create_root()
 
diff --git a/tests/configs/tsunami-simple-atomic-dual.py b/tests/configs/tsunami-simple-atomic-dual.py
index 9f827d9d9..f54015cd3 100644
--- a/tests/configs/tsunami-simple-atomic-dual.py
+++ b/tests/configs/tsunami-simple-atomic-dual.py
@@ -39,6 +39,6 @@ from m5.objects import *
 from alpha_generic import *
 
 root = LinuxAlphaFSSystem(mem_mode='atomic',
-                          mem_class=DDR3_1600_x64,
+                          mem_class=SimpleMemory,
                           cpu_class=AtomicSimpleCPU,
                           num_cpus=2).create_root()
diff --git a/tests/configs/tsunami-simple-atomic.py b/tests/configs/tsunami-simple-atomic.py
index 8c486204c..0cc19e092 100644
--- a/tests/configs/tsunami-simple-atomic.py
+++ b/tests/configs/tsunami-simple-atomic.py
@@ -39,5 +39,5 @@ from m5.objects import *
 from alpha_generic import *
 
 root = LinuxAlphaFSSystemUniprocessor(mem_mode='atomic',
-                                      mem_class=DDR3_1600_x64,
+                                      mem_class=SimpleMemory,
                                       cpu_class=AtomicSimpleCPU).create_root()