diff --git a/src/tt.cpp b/src/tt.cpp
index c1c15213..24e94c80 100644
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -30,7 +30,7 @@ TranspositionTable TT; // Our global transposition table
 /// measured in megabytes. Transposition table consists of a power of 2 number
 /// of clusters and each cluster consists of ClusterSize number of TTEntry.
 
-void TranspositionTable::set_size(size_t mbSize) {
+void TranspositionTable::set_size(uint64_t mbSize) {
 
   assert(msb((mbSize << 20) / sizeof(TTEntry)) < 32);
 
diff --git a/src/tt.h b/src/tt.h
index 7e580fec..a926d4ad 100644
--- a/src/tt.h
+++ b/src/tt.h
@@ -81,7 +81,7 @@ public:
   const TTEntry* probe(const Key key) const;
   TTEntry* first_entry(const Key key) const;
   void refresh(const TTEntry* tte) const;
-  void set_size(size_t mbSize);
+  void set_size(uint64_t mbSize);
   void clear();
   void store(const Key key, Value v, Bound type, Depth d, Move m, Value statV);
 
diff --git a/src/ucioption.cpp b/src/ucioption.cpp
index 0ef892bd..417765a5 100644
--- a/src/ucioption.cpp
+++ b/src/ucioption.cpp
@@ -73,7 +73,7 @@ void init(OptionsMap& o) {
   o["Max Threads per Split Point"] = Option(5, 4,  8, on_threads);
   o["Threads"]                     = Option(1, 1, MAX_THREADS, on_threads);
   o["Idle Threads Sleep"]          = Option(true);
-  o["Hash"]                        = Option(32, 1, 8192, on_hash_size);
+  o["Hash"]                        = Option(32, 1, 16384, on_hash_size);
   o["Clear Hash"]                  = Option(on_clear_hash);
   o["Ponder"]                      = Option(true);
   o["OwnBook"]                     = Option(false);