diff --git a/readerwritercircularbuffer.h b/readerwritercircularbuffer.h
index 072b544..603b89d 100644
--- a/readerwritercircularbuffer.h
+++ b/readerwritercircularbuffer.h
@@ -19,7 +19,11 @@
 #include "atomicops.h"
 
 #ifndef MOODYCAMEL_CACHE_LINE_SIZE
-#define MOODYCAMEL_CACHE_LINE_SIZE 64
+#if defined(__powerpc__) || defined(__powerpc64__) || defined(__ppc64__) || defined (__PPC64__) || defined(_ARCH_PPC64) || defined(_M_PPC)
+	#define MOODYCAMEL_CACHE_LINE_SIZE 128
+#else
+	#define MOODYCAMEL_CACHE_LINE_SIZE 64
+#endif
 #endif
 
 namespace moodycamel {
diff --git a/readerwriterqueue.h b/readerwriterqueue.h
index 78c8e43..8a3bb5c 100644
--- a/readerwriterqueue.h
+++ b/readerwriterqueue.h
@@ -33,7 +33,11 @@
 // Using the queue exclusively from one thread is fine, though a bit silly.
 
 #ifndef MOODYCAMEL_CACHE_LINE_SIZE
-#define MOODYCAMEL_CACHE_LINE_SIZE 64
+#if defined(__powerpc__) || defined(__powerpc64__) || defined(__ppc64__) || defined (__PPC64__) || defined(_ARCH_PPC64) || defined(_M_PPC)
+	#define MOODYCAMEL_CACHE_LINE_SIZE 128
+#else
+	#define MOODYCAMEL_CACHE_LINE_SIZE 64
+#endif
 #endif
 
 #ifndef MOODYCAMEL_EXCEPTIONS_ENABLED