diff --git a/config/x86_64/threads.h b/config/x86_64/threads.h
index a8b15d0..3e6452d 100644
--- a/config/x86_64/threads.h
+++ b/config/x86_64/threads.h
@@ -16,9 +16,9 @@
  * Set a default size for the stack.
  */
 #if defined(INTERPRETER)
-#define THREADSTACKSIZE         (128 * 1024)
+#define THREADSTACKSIZE         (1024 * 1024)
 #else
-#define THREADSTACKSIZE         (64 * 1024)
+#define THREADSTACKSIZE         (512 * 1024)
 #endif
 
 /*