diff --git a/src/FSharp.Data.Adaptive/Datastructures/Index.fs b/src/FSharp.Data.Adaptive/Datastructures/Index.fs
index 77720cf..60715d2 100644
--- a/src/FSharp.Data.Adaptive/Datastructures/Index.fs
+++ b/src/FSharp.Data.Adaptive/Datastructures/Index.fs
@@ -3,6 +3,7 @@
 open System
 open System.Threading
 open System.Collections.Generic
+open System.Runtime.CompilerServices
 
 /// the internal implementation of our order-maintenance structure.
 [<StructuredFormatDisplay("{AsString}")>]
@@ -138,6 +139,10 @@ type IndexNode =
             | false, false ->
                 x.CompareTo o
 
+        [<MethodImpl(MethodImplOptions.AggressiveInlining)>]
+        member x.Equals (o : IndexNode) =
+            System.Object.ReferenceEquals(x,o)
+
         interface IComparable with
             member x.CompareTo (o : obj) =
                 match o with
@@ -270,6 +275,10 @@ type Index private(real : IndexNode) =
     override x.ToString() = real.ToString()
     member private x.AsString = x.ToString()
 
+    interface IEquatable<Index> with
+        member x.Equals (o: Index): bool = 
+            real.Equals o.Value
+
     interface IComparable with
         member x.CompareTo(o : obj) = 
             match o with
diff --git a/src/FSharp.Data.Adaptive/Datastructures/Index.fsi b/src/FSharp.Data.Adaptive/Datastructures/Index.fsi
index 49f38bb..11d60b3 100644
--- a/src/FSharp.Data.Adaptive/Datastructures/Index.fsi
+++ b/src/FSharp.Data.Adaptive/Datastructures/Index.fsi
@@ -9,6 +9,7 @@ open System
 type Index =
     interface IComparable
     #if !FABLE_COMPILER
+    interface IEquatable<Index>
     interface IComparable<Index>
     #endif
 
diff --git a/src/Test/FSharp.Data.Adaptive.Tests/Benchmarks/IndexBenchmarks.fs b/src/Test/FSharp.Data.Adaptive.Tests/Benchmarks/IndexBenchmarks.fs
new file mode 100644
index 0000000..27a1fe1
--- /dev/null
+++ b/src/Test/FSharp.Data.Adaptive.Tests/Benchmarks/IndexBenchmarks.fs
@@ -0,0 +1,59 @@
+namespace Benchmarks
+
+open BenchmarkDotNet.Attributes
+open FSharp.Data.Adaptive
+
+//BenchmarkDotNet v0.14.0, Windows 10 (10.0.19045.4894/22H2/2022Update)
+//Intel Core i7-8700K CPU 3.70GHz (Coffee Lake), 1 CPU, 12 logical and 6 physical cores
+//.NET SDK 8.0.400
+//  [Host]     : .NET 8.0.8 (8.0.824.36612), X64 RyuJIT AVX2 DEBUG
+//  DefaultJob : .NET 8.0.8 (8.0.824.36612), X64 RyuJIT AVX2
+
+//| Method        | CreateCount | Mean     | Error   | StdDev  | Allocated |
+//|-------------- |------------ |---------:|--------:|--------:|----------:|
+//| HashSetAdd    | 10000       | 221.6 μs | 2.46 μs | 2.05 μs |         - |
+//| DictionaryAdd | 10000       | 230.2 μs | 0.59 μs | 0.55 μs |         - |
+
+// with Index IEquatable
+//| Method        | CreateCount | Mean     | Error   | StdDev  | Allocated |
+//|-------------- |------------ |---------:|--------:|--------:|----------:|
+//| HashSetAdd    | 10000       | 204.5 us | 0.37 us | 0.34 us |         - |
+//| DictionaryAdd | 10000       | 215.2 us | 2.46 us | 2.18 us |         - |
+
+// + inlined IndexNode Equals
+//| Method        | CreateCount | Mean     | Error   | StdDev  | Allocated |
+//|-------------- |------------ |---------:|--------:|--------:|----------:|
+//| HashSetAdd    | 10000       | 199.1 us | 3.85 us | 4.12 us |         - |
+//| DictionaryAdd | 10000       | 205.4 us | 1.43 us | 1.33 us |         - |
+
+[<MemoryDiagnoser>]
+type IndexEqualsBenchmarks() =
+
+    [<Params(10000); DefaultValue>]
+    val mutable public Count : int
+
+    let mutable indexSet = Unchecked.defaultof<_>
+    let mutable indexDict = Unchecked.defaultof<_>
+    let mutable indices = Array.empty
+
+    [<GlobalSetup>]
+    member x.Setup() =
+        indexSet <- System.Collections.Generic.HashSet<Index>(x.Count)
+        indexDict <- System.Collections.Generic.Dictionary<Index, int>(x.Count)
+        indices <- Array.zeroCreate x.Count
+        let mutable h = Index.zero
+        for i in 0..x.Count-1 do
+            h <- Index.after h
+            indices.[i] <- h
+
+    [<Benchmark>]
+    member x.HashSetAdd() =
+        for i in indices do
+            indexSet.Add(i) |> ignore
+
+    [<Benchmark>]
+    member x.DictionaryAdd() =
+        let mutable ii = 0
+        for i in indices do
+            indexDict.[i] <- ii
+            ii <- ii + 1
diff --git a/src/Test/FSharp.Data.Adaptive.Tests/FSharp.Data.Adaptive.Tests.fsproj b/src/Test/FSharp.Data.Adaptive.Tests/FSharp.Data.Adaptive.Tests.fsproj
index 11c51a5..c06707e 100644
--- a/src/Test/FSharp.Data.Adaptive.Tests/FSharp.Data.Adaptive.Tests.fsproj
+++ b/src/Test/FSharp.Data.Adaptive.Tests/FSharp.Data.Adaptive.Tests.fsproj
@@ -26,6 +26,7 @@
     <Compile Include="Benchmarks\HashSetDeltaBench.fs" />
     <Compile Include="Benchmarks\ListDeltaBenchmarks.fs" />
     <Compile Include="Benchmarks\IndexListBenchmarks.fs" />
+    <Compile Include="Benchmarks\IndexBenchmarks.fs" />
     <Compile Include="Utilities\Helpers.fs" />
     <Compile Include="Utilities\Generators.fs" />
     <Compile Include="Callbacks.fs" />
diff --git a/src/Test/FSharp.Data.Adaptive.Tests/Program.fs b/src/Test/FSharp.Data.Adaptive.Tests/Program.fs
index 28173dc..12fdc68 100644
--- a/src/Test/FSharp.Data.Adaptive.Tests/Program.fs
+++ b/src/Test/FSharp.Data.Adaptive.Tests/Program.fs
@@ -50,7 +50,7 @@ let main _args =
 
     //ASet.``[ASet] mapA/flattenA/chooseA async``()
     //ASet.``[ASet] union constant``()
-    AList.``[AList] toAset``()
+    //AList.``[AList] toAset``()
 
     //``[AList] sub``();
 
@@ -91,5 +91,6 @@ let main _args =
     //BenchmarkRunner.Run<Benchmarks.MapExtEnumeratorBenchmark>() |> ignore
     //BenchmarkRunner.Run<Benchmarks.HashSetDeltaBench>() |> ignore
     //BenchmarkRunner.Run<Benchmarks.IndexListBenchmarks>() |> ignore
+    BenchmarkRunner.Run<Benchmarks.IndexEqualsBenchmarks>() |> ignore
 
     0