diff --git a/src/package.ml b/src/package.ml
index fb7788ae..1b2d1577 100644
--- a/src/package.ml
+++ b/src/package.ml
@@ -1,7 +1,10 @@
 open Stdune
 
 module Name = struct
-  include Interned.Make(struct let resize_policy = Interned.Conservative end)
+  include Interned.Make(struct
+      let initial_size = 16
+      let resize_policy = Interned.Conservative
+    end)
 
   let of_string = make
 
diff --git a/src/stdune/interned.ml b/src/stdune/interned.ml
index af039be1..e3cfc92f 100644
--- a/src/stdune/interned.ml
+++ b/src/stdune/interned.ml
@@ -28,7 +28,11 @@ let new_size ~next ~size = function
     (next land (lnot (increment_size - 1))) + (increment_size * 2)
   | Greedy -> size * 2
 
-module Make(R : sig val resize_policy : resize_policy end) = struct
+module Make(R : sig
+    val resize_policy : resize_policy
+    val initial_size  : int
+  end)
+= struct
   type t = int
 
   let ids = Hashtbl.create 1024
@@ -44,7 +48,7 @@ module Make(R : sig val resize_policy : resize_policy end) = struct
 
     let create ~default_value =
       { default_value
-      ; data = [||]
+      ; data = Array.make R.initial_size default_value
       }
 
     let resize t =
diff --git a/src/stdune/interned.mli b/src/stdune/interned.mli
index fec0493a..2b71006c 100644
--- a/src/stdune/interned.mli
+++ b/src/stdune/interned.mli
@@ -36,4 +36,7 @@ end
 
 type resize_policy = Conservative | Greedy
 
-module Make(R : sig val resize_policy : resize_policy end) : S
+module Make(R : sig
+    val initial_size : int
+    val resize_policy : resize_policy
+  end) : S
diff --git a/src/sub_system_name.ml b/src/sub_system_name.ml
index e44b598f..14397bbf 100644
--- a/src/sub_system_name.ml
+++ b/src/sub_system_name.ml
@@ -1,3 +1,6 @@
 open Stdune
 
-include Interned.Make(struct let resize_policy = Interned.Conservative end)
+include Interned.Make(struct
+    let initial_size = 16
+    let resize_policy = Interned.Conservative
+  end)
diff --git a/src/variant.ml b/src/variant.ml
index 66d2c0de..548b4855 100644
--- a/src/variant.ml
+++ b/src/variant.ml
@@ -1,6 +1,9 @@
 open Stdune
 
-include Interned.Make(struct let resize_policy = Interned.Conservative end)
+include Interned.Make(struct
+    let initial_size = 256
+    let resize_policy = Interned.Conservative
+  end)
 
 let ppx_driver = make "ppx_driver"
 let mt         = make "mt"