diff --git a/src/Microsoft.VisualStudio.Threading/AsyncReaderWriterResourceLock.cs b/src/Microsoft.VisualStudio.Threading/AsyncReaderWriterResourceLock.cs
index 5671c94d8..b967d7d2f 100644
--- a/src/Microsoft.VisualStudio.Threading/AsyncReaderWriterResourceLock.cs
+++ b/src/Microsoft.VisualStudio.Threading/AsyncReaderWriterResourceLock.cs
@@ -477,7 +477,7 @@ internal class Helper
             /// <summary>
             /// A map of resources to the tasks that most recently began evaluating them.
             /// </summary>
-            private WeakKeyDictionary<TResource, ResourcePreparationTaskAndValidity> resourcePreparationTasks = new WeakKeyDictionary<TResource, ResourcePreparationTaskAndValidity>();
+            private WeakKeyDictionary<TResource, ResourcePreparationTaskAndValidity> resourcePreparationTasks = new WeakKeyDictionary<TResource, ResourcePreparationTaskAndValidity>(capacity: 2);
 
             /// <summary>
             /// Initializes a new instance of the <see cref="Helper"/> class.
diff --git a/src/Microsoft.VisualStudio.Threading/JoinableTaskCollection.cs b/src/Microsoft.VisualStudio.Threading/JoinableTaskCollection.cs
index 5fc071d61..e414d2eb9 100644
--- a/src/Microsoft.VisualStudio.Threading/JoinableTaskCollection.cs
+++ b/src/Microsoft.VisualStudio.Threading/JoinableTaskCollection.cs
@@ -26,14 +26,14 @@ public class JoinableTaskCollection : IEnumerable<JoinableTask>
         /// The value is the number of times the joinable was added to this collection (and not yet removed)
         /// if this collection is ref counted; otherwise the value is always 1.
         /// </summary>
-        private readonly WeakKeyDictionary<JoinableTask, int> joinables = new WeakKeyDictionary<JoinableTask, int>();
+        private readonly WeakKeyDictionary<JoinableTask, int> joinables = new WeakKeyDictionary<JoinableTask, int>(capacity: 2);
 
         /// <summary>
         /// The set of joinable tasks that have Joined this collection -- that is, the set of joinable tasks that are interested
         /// in the completion of any and all joinable tasks that belong to this collection.
         /// The value is the number of times a particular joinable task has Joined this collection.
         /// </summary>
-        private readonly WeakKeyDictionary<JoinableTask, int> joiners = new WeakKeyDictionary<JoinableTask, int>();
+        private readonly WeakKeyDictionary<JoinableTask, int> joiners = new WeakKeyDictionary<JoinableTask, int>(capacity: 2);
 
         /// <summary>
         /// A value indicating whether joinable tasks are only removed when completed or removed as many times as they were added.