diff --git a/include/verilated_heavy.h b/include/verilated_heavy.h
index c5409364a..f6cb8dd71 100644
--- a/include/verilated_heavy.h
+++ b/include/verilated_heavy.h
@@ -32,6 +32,7 @@
 #include <memory>
 #include <set>
 #include <string>
+#include <unordered_set>
 
 //===================================================================
 // String formatters (required by below containers)
@@ -267,7 +268,7 @@ public:
     void shuffle() { std::shuffle(m_deque.begin(), m_deque.end(), VlURNG()); }
     VlQueue unique() const {
         VlQueue out;
-        std::set<T_Value> saw;
+        std::unordered_set<T_Value> saw;
         for (const auto& i : m_deque) {
             auto it = saw.find(i);
             if (it == saw.end()) {
@@ -280,7 +281,7 @@ public:
     VlQueue<IData> unique_index() const {
         VlQueue<IData> out;
         IData index = 0;
-        std::set<T_Value> saw;
+        std::unordered_set<T_Value> saw;
         for (const auto& i : m_deque) {
             auto it = saw.find(i);
             if (it == saw.end()) {
diff --git a/include/verilated_syms.h b/include/verilated_syms.h
index c8f8514fc..29fdfcb90 100644
--- a/include/verilated_syms.h
+++ b/include/verilated_syms.h
@@ -31,6 +31,7 @@
 #include "verilated_sym_props.h"
 
 #include <map>
+#include <unordered_map>
 #include <vector>
 
 //======================================================================
@@ -58,7 +59,8 @@ public:
 
 typedef std::vector<const VerilatedScope*> VerilatedScopeVector;
 
-class VerilatedHierarchyMap final : public std::map<const VerilatedScope*, VerilatedScopeVector> {
+class VerilatedHierarchyMap final
+    : public std::unordered_map<const VerilatedScope*, VerilatedScopeVector> {
 public:
     VerilatedHierarchyMap() = default;
     ~VerilatedHierarchyMap() = default;
diff --git a/include/verilated_vpi.cpp b/include/verilated_vpi.cpp
index 3f0b34218..104383c2a 100644
--- a/include/verilated_vpi.cpp
+++ b/include/verilated_vpi.cpp
@@ -497,7 +497,7 @@ public:
         assertOneCheck();
         VpioCbList& cbObjList = s_s.m_cbObjLists[cbValueChange];
         bool called = false;
-        typedef std::set<VerilatedVpioVar*> VpioVarSet;
+        typedef std::unordered_set<VerilatedVpioVar*> VpioVarSet;
         VpioVarSet update;  // set of objects to update after callbacks
         if (cbObjList.empty()) return called;
         const auto last = std::prev(cbObjList.end());  // prevent looping over newly added elements
diff --git a/src/V3Delayed.cpp b/src/V3Delayed.cpp
index c03478ad1..096dbe912 100644
--- a/src/V3Delayed.cpp
+++ b/src/V3Delayed.cpp
@@ -98,7 +98,7 @@ private:
     typedef std::map<const std::pair<AstNodeModule*, string>, AstVar*> VarMap;
     VarMap m_modVarMap;  // Table of new var names created under module
     VDouble0 m_statSharedSet;  // Statistic tracking
-    typedef std::map<const AstVarScope*, int> ScopeVecMap;
+    typedef std::unordered_map<const AstVarScope*, int> ScopeVecMap;
     ScopeVecMap m_scopeVecMap;  // Next var number for each scope
 
     // METHODS
diff --git a/src/V3EmitCSyms.cpp b/src/V3EmitCSyms.cpp
index fe2ef52f8..3c8fb2e6e 100644
--- a/src/V3EmitCSyms.cpp
+++ b/src/V3EmitCSyms.cpp
@@ -109,7 +109,7 @@ class EmitCSyms final : EmitCBaseVisitor {
     int m_numStmts = 0;  // Number of statements output
     int m_funcNum = 0;  // CFunc split function number
     V3OutCFile* m_ofpBase = nullptr;  // Base (not split) C file
-    std::map<int, bool> m_usesVfinal;  // Split method uses __Vfinal
+    std::unordered_map<int, bool> m_usesVfinal;  // Split method uses __Vfinal
 
     // METHODS
     void emitSymHdr();
diff --git a/src/V3Gate.cpp b/src/V3Gate.cpp
index 72aca1174..7049a14a4 100644
--- a/src/V3Gate.cpp
+++ b/src/V3Gate.cpp
@@ -906,7 +906,7 @@ void GateVisitor::optimizeElimVar(AstVarScope* varscp, AstNode* substp, AstNode*
 class GateDedupeHash final : public V3HashedUserSame {
 public:
     // TYPES
-    typedef std::set<AstNode*> NodeSet;
+    typedef std::unordered_set<AstNode*> NodeSet;
 
 private:
     // NODE STATE
diff --git a/src/V3Graph.cpp b/src/V3Graph.cpp
index 1e7216bfd..518c1ce70 100644
--- a/src/V3Graph.cpp
+++ b/src/V3Graph.cpp
@@ -335,7 +335,7 @@ void V3Graph::dumpDotFile(const string& filename, bool colorAsSubgraph) const {
 
     // We use a map here, as we don't want to corrupt anything (userp) in the graph,
     // and we don't care if this is slow.
-    std::map<const V3GraphVertex*, int> numMap;
+    std::unordered_map<const V3GraphVertex*, int> numMap;
 
     // Print vertices
     int n = 0;
diff --git a/src/V3GraphDfa.cpp b/src/V3GraphDfa.cpp
index 7669fa619..3d193aca3 100644
--- a/src/V3GraphDfa.cpp
+++ b/src/V3GraphDfa.cpp
@@ -294,7 +294,7 @@ private:
             UINFO(9, "  On dfaState " << dfaStatep << endl);
 
             // From this dfaState, what corresponding nfaStates have what inputs?
-            std::set<int> inputs;
+            std::unordered_set<int> inputs;
             // Foreach NFA state (this DFA state was formed from)
             for (V3GraphEdge* dfaEdgep = dfaStatep->outBeginp(); dfaEdgep;
                  dfaEdgep = dfaEdgep->outNextp()) {
diff --git a/src/V3GraphStream.h b/src/V3GraphStream.h
index cc53b9e9d..f7bd78cb5 100644
--- a/src/V3GraphStream.h
+++ b/src/V3GraphStream.h
@@ -81,7 +81,7 @@ private:
     };
 
     typedef std::set<VxHolder, VxHolderCmp&> ReadyVertices;
-    typedef std::unordered_map<const V3GraphVertex*, VxHolder> WaitingVertices;
+    typedef std::map<const V3GraphVertex*, VxHolder> WaitingVertices;
 
     // MEMBERS
     VxHolderCmp m_vxHolderCmp;  // Vertext comparison functor
diff --git a/src/V3Hashed.cpp b/src/V3Hashed.cpp
index 459bed724..a72e45106 100644
--- a/src/V3Hashed.cpp
+++ b/src/V3Hashed.cpp
@@ -153,7 +153,7 @@ void V3Hashed::dumpFile(const string& filename, bool tree) {
     const std::unique_ptr<std::ofstream> logp(V3File::new_ofstream(filename));
     if (logp->fail()) v3fatal("Can't write " << filename);
 
-    std::map<int, int> dist;
+    std::unordered_map<int, int> dist;
 
     V3Hash lasthash;
     int num_in_bucket = 0;
diff --git a/src/V3HierBlock.cpp b/src/V3HierBlock.cpp
index be21161e2..41f647826 100644
--- a/src/V3HierBlock.cpp
+++ b/src/V3HierBlock.cpp
@@ -240,7 +240,7 @@ class HierBlockUsageCollectVisitor final : public AstNVisitor {
     AstUser1InUse m_inuser1;
 
     // STATE
-    typedef std::set<const AstModule*> ModuleSet;
+    typedef std::unordered_set<const AstModule*> ModuleSet;
     V3HierBlockPlan* const m_planp;
     AstModule* m_modp = nullptr;  // The current module
     AstModule* m_hierBlockp = nullptr;  // The nearest parent module that is a hierarchical block
@@ -355,7 +355,8 @@ void V3HierBlockPlan::createPlan(AstNetlist* nodep) {
 }
 
 V3HierBlockPlan::HierVector V3HierBlockPlan::hierBlocksSorted() const {
-    typedef std::map<const V3HierBlock*, std::set<const V3HierBlock*>> ChildrenMap;
+    typedef std::unordered_map<const V3HierBlock*, std::unordered_set<const V3HierBlock*>>
+        ChildrenMap;
     ChildrenMap childrenOfHierBlock;
 
     HierVector sorted;
diff --git a/src/V3HierBlock.h b/src/V3HierBlock.h
index e5409d1fd..7ce652a74 100644
--- a/src/V3HierBlock.h
+++ b/src/V3HierBlock.h
@@ -29,6 +29,7 @@
 #include <set>
 #include <string>
 #include <utility>
+#include <unordered_set>
 #include <vector>
 
 class AstNodeModule;
@@ -40,8 +41,8 @@ class AstVar;
 class V3HierBlock final {
 public:
     typedef std::vector<AstVar*> GParams;
-    typedef std::set<V3HierBlock*> HierBlockSet;
-    typedef std::set<const AstNodeModule*> NodeModuleSet;
+    typedef std::unordered_set<V3HierBlock*> HierBlockSet;
+    typedef std::unordered_set<const AstNodeModule*> NodeModuleSet;
 
 private:
     // TYPES
@@ -96,7 +97,7 @@ public:
 
 // Holds relashonship between AstNodeModule and V3HierBlock
 class V3HierBlockPlan final {
-    typedef std::map<const AstNodeModule*, V3HierBlock*> HierMap;
+    typedef std::unordered_map<const AstNodeModule*, V3HierBlock*> HierMap;
     HierMap m_blocks;
 
     V3HierBlockPlan() = default;
diff --git a/src/V3Inline.cpp b/src/V3Inline.cpp
index 829cf1e6c..c72990a3a 100644
--- a/src/V3Inline.cpp
+++ b/src/V3Inline.cpp
@@ -74,10 +74,10 @@ private:
 
     // Within the context of a given module, LocalInstanceMap maps
     // from child modules to the count of each child's local instantiations.
-    typedef std::map<AstNodeModule*, int> LocalInstanceMap;
+    typedef std::unordered_map<AstNodeModule*, int> LocalInstanceMap;
 
     // We keep a LocalInstanceMap for each module in the design
-    std::map<AstNodeModule*, LocalInstanceMap> m_instances;
+    std::unordered_map<AstNodeModule*, LocalInstanceMap> m_instances;
 
     // METHODS
     VL_DEBUG_FUNC;  // Declare debug()
diff --git a/src/V3Life.cpp b/src/V3Life.cpp
index fc4708235..daa9028f5 100644
--- a/src/V3Life.cpp
+++ b/src/V3Life.cpp
@@ -123,7 +123,7 @@ class LifeBlock final {
 
     // LIFE MAP
     //  For each basic block, we'll make a new map of what variables that if/else is changing
-    typedef std::map<AstVarScope*, LifeVarEntry> LifeMap;
+    typedef std::unordered_map<AstVarScope*, LifeVarEntry> LifeMap;
     LifeMap m_map;  // Current active lifetime map for current scope
     LifeBlock* m_aboveLifep;  // Upper life, or nullptr
     LifeState* m_statep;  // Current global state
@@ -278,7 +278,7 @@ private:
 
     // LIFE MAP
     //  For each basic block, we'll make a new map of what variables that if/else is changing
-    typedef std::map<AstVarScope*, LifeVarEntry> LifeMap;
+    typedef std::unordered_map<AstVarScope*, LifeVarEntry> LifeMap;
     // cppcheck-suppress memleak  // cppcheck bug - it is deleted
     LifeBlock* m_lifep;  // Current active lifetime map for current scope
 
diff --git a/src/V3LinkDot.cpp b/src/V3LinkDot.cpp
index 798dd23c8..5ddf96eb6 100644
--- a/src/V3LinkDot.cpp
+++ b/src/V3LinkDot.cpp
@@ -141,7 +141,7 @@ public:
 private:
     // TYPES
     typedef std::multimap<string, VSymEnt*> NameScopeSymMap;
-    typedef std::map<VSymEnt*, VSymEnt*> ScopeAliasMap;
+    typedef std::unordered_map<VSymEnt*, VSymEnt*> ScopeAliasMap;
     typedef std::set<std::pair<AstNodeModule*, string>> ImplicitNameSet;
     typedef std::vector<VSymEnt*> IfaceVarSyms;
     typedef std::vector<std::pair<AstIface*, VSymEnt*>> IfaceModSyms;
diff --git a/src/V3LinkParse.cpp b/src/V3LinkParse.cpp
index 2dce23b64..a3883b91c 100644
--- a/src/V3LinkParse.cpp
+++ b/src/V3LinkParse.cpp
@@ -45,7 +45,7 @@ private:
 
     // TYPES
     typedef std::map<const std::pair<void*, string>, AstTypedef*> ImplTypedefMap;
-    typedef std::set<FileLine*> FileLineSet;
+    typedef std::unordered_set<FileLine*> FileLineSet;
 
     // STATE
     AstVar* m_varp = nullptr;  // Variable we're under
diff --git a/src/V3Param.cpp b/src/V3Param.cpp
index 6c491ae5e..91def7f9f 100644
--- a/src/V3Param.cpp
+++ b/src/V3Param.cpp
@@ -216,7 +216,7 @@ private:
     typedef std::deque<std::pair<AstIfaceRefDType*, AstIfaceRefDType*>> IfaceRefRefs;
 
     // STATE
-    typedef std::map<const AstNode*, AstNode*> CloneMap;
+    typedef std::unordered_map<const AstNode*, AstNode*> CloneMap;
     struct ModInfo {
         AstNodeModule* m_modp;  // Module with specified name
         CloneMap m_cloneMap;  // Map of old-varp -> new cloned varp
diff --git a/src/V3Simulate.h b/src/V3Simulate.h
index 6a251e905..edec6cffe 100644
--- a/src/V3Simulate.h
+++ b/src/V3Simulate.h
@@ -61,7 +61,7 @@ public:
 };
 
 typedef std::deque<AstConst*> ConstDeque;
-typedef std::map<const AstNodeDType*, ConstDeque> ConstPile;
+typedef std::unordered_map<const AstNodeDType*, ConstDeque> ConstPile;
 
 class SimulateVisitor VL_NOT_FINAL : public AstNVisitor {
     // Simulate a node tree, returning value of variables
diff --git a/src/V3String.h b/src/V3String.h
index af5437092..6bc0bd61f 100644
--- a/src/V3String.h
+++ b/src/V3String.h
@@ -23,8 +23,9 @@
 // No V3 headers here - this is a base class for Vlc etc
 
 #include <map>
-#include <string>
 #include <sstream>
+#include <string>
+#include <unordered_map>
 #include <vector>
 
 //######################################################################
diff --git a/src/V3SymTable.h b/src/V3SymTable.h
index 512bdedf1..0b0cd7242 100644
--- a/src/V3SymTable.h
+++ b/src/V3SymTable.h
@@ -36,7 +36,7 @@ class VSymEnt;
 //######################################################################
 // Symbol table
 
-typedef std::set<const VSymEnt*> VSymConstMap;
+typedef std::unordered_set<const VSymEnt*> VSymConstMap;
 
 class VSymEnt final {
     // Symbol table that can have a "superior" table for resolving upper references
diff --git a/src/V3Task.cpp b/src/V3Task.cpp
index 11829195d..38afb4c39 100644
--- a/src/V3Task.cpp
+++ b/src/V3Task.cpp
@@ -104,7 +104,7 @@ private:
 
     // TYPES
     typedef std::map<std::pair<AstScope*, AstVar*>, AstVarScope*> VarToScopeMap;
-    typedef std::map<const AstNodeFTask*, AstClass*> FuncToClassMap;
+    typedef std::unordered_map<const AstNodeFTask*, AstClass*> FuncToClassMap;
     typedef std::vector<AstInitial*> Initials;
     // MEMBERS
     VarToScopeMap m_varToScopeMap;  // Map for Var -> VarScope mappings
diff --git a/src/V3Tristate.cpp b/src/V3Tristate.cpp
index 8988b6258..237636f14 100644
--- a/src/V3Tristate.cpp
+++ b/src/V3Tristate.cpp
@@ -329,7 +329,7 @@ class TristateVisitor final : public TristateBaseVisitor {
 
     // TYPES
     typedef std::vector<AstVarRef*> RefVec;
-    typedef std::map<AstVar*, RefVec*> VarMap;
+    typedef std::unordered_map<AstVar*, RefVec*> VarMap;
     enum : uint8_t {
         U2_GRAPHING = 1,  // bit[0] if did m_graphing visit
         U2_NONGRAPH = 2,  // bit[1] if did !m_graphing visit