diff --git a/DRAMSys/simulator/src/simulation/Dram.h b/DRAMSys/simulator/src/simulation/Dram.h
index 85dfdf8a..db47d6cf 100644
--- a/DRAMSys/simulator/src/simulation/Dram.h
+++ b/DRAMSys/simulator/src/simulation/Dram.h
@@ -66,6 +66,8 @@ using namespace Data;
 struct Dram : sc_module
 {
     unsigned int burstLength  = Configuration::getInstance().memSpec.BurstLength;
+    // All DRAM chips on a DIMM operate in lockstep,
+    // which constituing aggregate data bus width = chip's bus width * # locksteep-operated chips
     unsigned int busWidth = Configuration::getInstance().memSpec.BusWidth * Configuration::getInstance().NumberOfDevicesOnDIMM;
     unsigned int bytesPerBurst = burstLength * (busWidth / 8);
 
@@ -94,11 +96,11 @@ struct Dram : sc_module
 
     SC_CTOR(Dram) : tSocket("socket")
     {
-        // calculate memory size
+        // calculate memory size (in Bytes)
         unsigned int banks = Configuration::getInstance().memSpec.NumberOfBanks;
         unsigned int rows = Configuration::getInstance().memSpec.NumberOfRows;
         unsigned int columns = Configuration::getInstance().memSpec.NumberOfColumns;
-        unsigned int size = banks * rows * columns;
+        unsigned int size = banks * rows * columns * (busWidth / 8);
         memory = (unsigned char *)mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON | MAP_NORESERVE, -1, 0);
 
         tSocket.register_nb_transport_fw(this, &Dram::nb_transport_fw);