diff --git a/src/mainboard/lenovo/t400/cstates.c b/src/mainboard/lenovo/t400/cstates.c
index 3ce2ed1a81..175153ebd4 100644
--- a/src/mainboard/lenovo/t400/cstates.c
+++ b/src/mainboard/lenovo/t400/cstates.c
@@ -28,6 +28,11 @@ static acpi_cstate_t cst_entries[] = {
 		2, 0x01,  500,
 		{ ACPI_ADDRESS_SPACE_FIXED, 1, 2, { 1 }, 0x10, 0 }
 	},
+	{
+		/* acpi C3 / cpu C3 */
+		3, 0x37,  250,
+		{ ACPI_ADDRESS_SPACE_FIXED, 1, 2, { 1 }, 0x20, 0 }
+	},
 };
 
 int get_cst_entries(acpi_cstate_t **entries)
diff --git a/src/mainboard/lenovo/t400/devicetree.cb b/src/mainboard/lenovo/t400/devicetree.cb
index 43a610ab5f..6bf25fab38 100644
--- a/src/mainboard/lenovo/t400/devicetree.cb
+++ b/src/mainboard/lenovo/t400/devicetree.cb
@@ -63,7 +63,7 @@ chip northbridge/intel/gm45
 			register "sata_traffic_monitor"		= "0"
 
 			# Set c-state support
-			register "c4onc3_enable"		= "0"
+			register "c4onc3_enable"		= "1"
 			register "c5_enable"			= "1"
 			register "c6_enable"			= "1"
 
diff --git a/src/mainboard/lenovo/x200/cstates.c b/src/mainboard/lenovo/x200/cstates.c
index 3ce2ed1a81..175153ebd4 100644
--- a/src/mainboard/lenovo/x200/cstates.c
+++ b/src/mainboard/lenovo/x200/cstates.c
@@ -28,6 +28,11 @@ static acpi_cstate_t cst_entries[] = {
 		2, 0x01,  500,
 		{ ACPI_ADDRESS_SPACE_FIXED, 1, 2, { 1 }, 0x10, 0 }
 	},
+	{
+		/* acpi C3 / cpu C3 */
+		3, 0x37,  250,
+		{ ACPI_ADDRESS_SPACE_FIXED, 1, 2, { 1 }, 0x20, 0 }
+	},
 };
 
 int get_cst_entries(acpi_cstate_t **entries)
diff --git a/src/mainboard/lenovo/x200/devicetree.cb b/src/mainboard/lenovo/x200/devicetree.cb
index 9f5bb41577..200b4bca0f 100644
--- a/src/mainboard/lenovo/x200/devicetree.cb
+++ b/src/mainboard/lenovo/x200/devicetree.cb
@@ -67,7 +67,7 @@ chip northbridge/intel/gm45
 			register "sata_traffic_monitor"		= "0"
 
 			# Set c-state support
-			register "c4onc3_enable"		= "0"
+			register "c4onc3_enable"		= "1"
 			register "c5_enable"			= "1"
 			register "c6_enable"			= "1"