diff --git a/rocket/src/main/scala/consts.scala b/rocket/src/main/scala/consts.scala
index 51071105..e4af3ec6 100644
--- a/rocket/src/main/scala/consts.scala
+++ b/rocket/src/main/scala/consts.scala
@@ -195,8 +195,8 @@ object Constants
   val COHERENCE_DATA_BITS = (1 << OFFSET_BITS)*8 
   val TILE_ID_BITS = log2Up(NTILES)+1
   val TILE_XACT_ID_BITS = log2Up(NMSHR)+3
-  val GLOBAL_XACT_ID_BITS = log2Up(NTILES*NMSHR)+1
-  val NGLOBAL_XACTS = 1 << GLOBAL_XACT_ID_BITS
+  val NGLOBAL_XACTS = 8
+  val GLOBAL_XACT_ID_BITS = log2Up(NGLOBAL_XACTS)
 
   val X_INIT_TYPE_MAX_BITS = 2
   val X_REP_TYPE_MAX_BITS = 3