--- a/hotspot/src/cpu/x86/vm/vm_version_x86.cpp	Fri Mar 11 22:34:57 2011 -0800
+++ b/hotspot/src/cpu/x86/vm/vm_version_x86.cpp	Thu Mar 17 12:08:01 2011 -0700
@@ -436,6 +436,13 @@
         UseCountLeadingZerosInstruction = true;
       }
     }
+
+    // On family 21 processors default is no sw prefetch
+    if ( cpu_family() == 21 ) {
+      if (FLAG_IS_DEFAULT(AllocatePrefetchStyle)) {
+        AllocatePrefetchStyle = 0;
+      }
+    }
   }
 
   if( is_intel() ) { // Intel cpus specific settings