Increase new space size and limits on 64-bit platforms.

src/heap.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 834 matching lines @@
 
   // For keeping track of how much data has survived
   // scavenge since last new space expansion.
   static int survived_since_last_expansion_;
 
   static int always_allocate_scope_depth_;
   static bool context_disposed_pending_;
 
   static const int kMaxMapSpaceSize = 8*MB;
 
+#if defined(V8_TARGET_ARCH_X64)
+  static const int kMaxObjectSizeInNewSpace = 512*KB;
+#else
   static const int kMaxObjectSizeInNewSpace = 256*KB;
+#endif
 
   static NewSpace new_space_;
   static OldSpace* old_pointer_space_;
   static OldSpace* old_data_space_;
   static OldSpace* code_space_;
   static MapSpace* map_space_;
   static CellSpace* cell_space_;
   static LargeObjectSpace* lo_space_;
   static HeapState gc_state_;
 
@@ skipping 601 matching lines @@
   int marked_count_;
 
   // The count from the end of the previous full GC.  Will be zero if there
   // was no previous full GC.
   int previous_marked_count_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_