diff --git a/src/tt.cpp b/src/tt.cpp
index 0a3c54a1..92aaee00 100644
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -65,8 +65,10 @@ void TranspositionTable::resize(size_t mbSize) {
 
   aligned_ttmem_free(mem);
 
-  clusterCount = mbSize * 1024 * 1024 / sizeof(Cluster);
-  table = static_cast<Cluster*>(aligned_ttmem_alloc(clusterCount * sizeof(Cluster), mem));
+  superClusterCount = mbSize * 1024 * 1024 / (sizeof(Cluster) * ClustersPerSuperCluster);
+
+  table = static_cast<Cluster*>(
+      aligned_ttmem_alloc(superClusterCount * ClustersPerSuperCluster * sizeof(Cluster), mem));
   if (!mem)
   {
       std::cerr << "Failed to allocate " << mbSize
@@ -89,6 +91,8 @@ void TranspositionTable::clear() {
   {
       threads.emplace_back([this, idx]() {
 
+          const size_t clusterCount = superClusterCount * ClustersPerSuperCluster;
+
           // Thread binding gives faster search on systems with a first-touch policy
           if (Options["Threads"] > 8)
               WinProcGroup::bindThisThread(idx);
diff --git a/src/tt.h b/src/tt.h
index bd723a86..76db03da 100644
--- a/src/tt.h
+++ b/src/tt.h
@@ -66,6 +66,7 @@ private:
 class TranspositionTable {
 
   static constexpr int ClusterSize = 3;
+  static constexpr int ClustersPerSuperCluster = 256;
 
   struct Cluster {
     TTEntry entry[ClusterSize];
@@ -82,15 +83,21 @@ public:
   void resize(size_t mbSize);
   void clear();
 
-  // The 32 lowest order bits of the key are used to get the index of the cluster
   TTEntry* first_entry(const Key key) const {
-    return &table[(uint32_t(key) * uint64_t(clusterCount)) >> 32].entry[0];
+
+    // The index is computed from
+    // Idx = (K48 * SCC) / 2^40, with K48 the 48 lowest bits swizzled.
+
+    const uint64_t firstTerm =  uint32_t(key) * uint64_t(superClusterCount);
+    const uint64_t secondTerm = (uint16_t(key >> 32) * uint64_t(superClusterCount)) >> 16;
+
+    return &table[(firstTerm + secondTerm) >> 24].entry[0];
   }
 
 private:
   friend struct TTEntry;
 
-  size_t clusterCount;
+  size_t superClusterCount;
   Cluster* table;
   void* mem;
   uint8_t generation8; // Size must be not bigger than TTEntry::genBound8
diff --git a/src/ucioption.cpp b/src/ucioption.cpp
index 16add76e..90190b53 100644
--- a/src/ucioption.cpp
+++ b/src/ucioption.cpp
@@ -56,8 +56,8 @@ bool CaseInsensitiveLess::operator() (const string& s1, const string& s2) const
 
 void init(OptionsMap& o) {
 
-  // at most 2^32 clusters.
-  constexpr int MaxHashMB = Is64Bit ? 131072 : 2048;
+  // At most 2^32 superclusters. Supercluster = 8 kB
+  constexpr int MaxHashMB = Is64Bit ? 33554432 : 2048;
 
   o["Debug Log File"]        << Option("", on_logger);
   o["Contempt"]              << Option(24, -100, 100);