diff --git a/DRAMSys/traceAnalyzer/scripts/metrics.py b/DRAMSys/traceAnalyzer/scripts/metrics.py
index 460c3f33..fed580c6 100644
--- a/DRAMSys/traceAnalyzer/scripts/metrics.py
+++ b/DRAMSys/traceAnalyzer/scripts/metrics.py
@@ -254,7 +254,7 @@ def bank_overlap_ratio(connection):
     cursor.execute("""
         select p1.PhaseBegin, p1.PhaseName from Phases p1
         where
-        (p1.PhaseName = "ACT" or p1.PhaseName = "PRE_ALL" or p1.PhaseName = "PRE" or p1.PhaseName = "RDA" or p1.PhaseName = "WRA")
+        (p1.PhaseName = "ACT" or p1.PhaseName = "PRE_ALL" or p1.PhaseName = "PRE" or p1.PhaseName = "RDA" or p1.PhaseName = "WRA" or p1.PhaseName = "PREB" or p1.PhaseName = "ACTB")
         order by PhaseBegin
         """)
     prevPhase = "PRE_ALL"
@@ -273,7 +273,10 @@ def bank_overlap_ratio(connection):
         bankTime.append(0)
 
     currentTime = 0
+    validBankRange = range(0, getNumberOfBanks(connection) + 1)
 
+    # RGR uses ACTB and PREB for refresh
+    actbCnt = 0
     for t in trace:
 
         interval = t[0] - currentTime
@@ -282,14 +285,38 @@ def bank_overlap_ratio(connection):
 
         if(t[1] == "ACT"):
             bankCounter += 1
+            if not (bankCounter in validBankRange):
+                print("Unexpected ACT. bankCounter was {0} valid range is python range {1}".format(bankCounter, validBankRange))
+        elif t[1] == "ACTB":
+            actbCnt += 1
         elif(t[1] == "PRE_ALL"):
             bankCounter = 0
         elif(t[1] == "PRE"):
-            bankCounter -= 1
+            if (bankCounter > 0):
+                bankCounter -= 1
+            else:
+                print("Unexpected PRE. bankCounter was {0} valid range is python range {1}".format(bankCounter, validBankRange))
+        elif(t[1] == "PREB"):
+            # RGR first PREB closes the row ACT follows, then PREB again.
+            if actbCnt > 0:
+                # Ignore the second PREB
+                actbCnt -= 1
+            else:
+                # Treat the first PREB which closes the row
+                if bankCounter > 0:
+                    bankCounter -= 1
+                else:
+                    print("Unexpected PREB. bankCounter was {0} valid range is python range {1}".format(bankCounter, validBankRange))
         elif(t[1] == "WRA"):
-            bankCounter -= 1
+            if (bankCounter > 0):
+                bankCounter -= 1
+            else:
+                print("Unexpected WRA. bankCounter was {0} valid range is python range {1}".format(bankCounter, validBankRange))
         elif(t[1] == "RDA"):
-            bankCounter -= 1
+            if (bankCounter > 0):
+                bankCounter -= 1
+            else:
+                print("Unexpected RDA. bankCounter was {0} valid range is python range {1}".format(bankCounter, validBankRange))
         else:
             print("ERROR")
             return 0