diff --git a/core/genesis.go b/core/genesis.go
index 42836e0269..738e68cb45 100644
--- a/core/genesis.go
+++ b/core/genesis.go
@@ -624,7 +624,7 @@ func decodePrealloc(data string) types.GenesisAlloc {
 			acc.Nonce = account.Misc.Nonce
 			acc.Code = account.Misc.Code
 
-			acc.Storage = make(map[common.Hash]common.Hash)
+			acc.Storage = make(map[common.Hash]common.Hash, len(account.Misc.Slots))
 			for _, slot := range account.Misc.Slots {
 				acc.Storage[slot.Key] = slot.Val
 			}
diff --git a/node/rpcstack.go b/node/rpcstack.go
index 6d3828ec2b..4e85c5bb3b 100644
--- a/node/rpcstack.go
+++ b/node/rpcstack.go
@@ -436,7 +436,7 @@ type virtualHostHandler struct {
 }
 
 func newVHostHandler(vhosts []string, next http.Handler) http.Handler {
-	vhostMap := make(map[string]struct{})
+	vhostMap := make(map[string]struct{}, len(vhosts))
 	for _, allowedHost := range vhosts {
 		vhostMap[strings.ToLower(allowedHost)] = struct{}{}
 	}
@@ -636,7 +636,7 @@ func RegisterApis(apis []rpc.API, modules []string, srv *rpc.Server) error {
 		log.Error("Unavailable modules in HTTP API list", "unavailable", bad, "available", available)
 	}
 	// Generate the allow list based on the allowed modules
-	allowList := make(map[string]bool)
+	allowList := make(map[string]bool, len(modules))
 	for _, module := range modules {
 		allowList[module] = true
 	}
diff --git a/rpc/server.go b/rpc/server.go
index 52866004f8..47f15b1dd2 100644
--- a/rpc/server.go
+++ b/rpc/server.go
@@ -190,7 +190,7 @@ func (s *RPCService) Modules() map[string]string {
 	s.server.services.mu.Lock()
 	defer s.server.services.mu.Unlock()
 
-	modules := make(map[string]string)
+	modules := make(map[string]string, len(s.server.services.services))
 	for name := range s.server.services.services {
 		modules[name] = "1.0"
 	}
diff --git a/triedb/pathdb/nodebuffer.go b/triedb/pathdb/nodebuffer.go
index 5675f14123..ff09484100 100644
--- a/triedb/pathdb/nodebuffer.go
+++ b/triedb/pathdb/nodebuffer.go
@@ -90,7 +90,7 @@ func (b *nodebuffer) commit(nodes map[common.Hash]map[string]*trienode.Node) *no
 			// The nodes belong to original diff layer are still accessible even
 			// after merging, thus the ownership of nodes map should still belong
 			// to original layer and any mutation on it should be prevented.
-			current = make(map[string]*trienode.Node)
+			current = make(map[string]*trienode.Node, len(subset))
 			for path, n := range subset {
 				current[path] = n
 				delta += int64(len(n.Blob) + len(path))