diff --git a/src/Speckle.Sdk.Dependencies/Serialization/ChannelLoader.cs b/src/Speckle.Sdk.Dependencies/Serialization/ChannelLoader.cs
index a05b7d7f..43f49e5d 100644
--- a/src/Speckle.Sdk.Dependencies/Serialization/ChannelLoader.cs
+++ b/src/Speckle.Sdk.Dependencies/Serialization/ChannelLoader.cs
@@ -5,7 +5,7 @@ namespace Speckle.Sdk.Dependencies.Serialization;
 
 public abstract class ChannelLoader<T>(CancellationToken cancellationToken)
 {
-  private const int RECEIVE_CAPACITY = 5000;
+  private const int RECEIVE_CAPACITY = 10000;
 
   private const int HTTP_GET_CHUNK_SIZE = 500;
   private const int MAX_PARALLELISM_HTTP = 4;
diff --git a/src/Speckle.Sdk.Dependencies/Serialization/ChannelSaver.cs b/src/Speckle.Sdk.Dependencies/Serialization/ChannelSaver.cs
index 37d1b999..b688f3a2 100644
--- a/src/Speckle.Sdk.Dependencies/Serialization/ChannelSaver.cs
+++ b/src/Speckle.Sdk.Dependencies/Serialization/ChannelSaver.cs
@@ -8,7 +8,7 @@ namespace Speckle.Sdk.Dependencies.Serialization;
 public abstract class ChannelSaver<T>
   where T : IHasByteSize
 {
-  private const int SEND_CAPACITY = 1000;
+  private const int SEND_CAPACITY = 10000;
   private const int HTTP_SEND_CHUNK_SIZE = 25_000_000; //bytes
   private static readonly TimeSpan HTTP_BATCH_TIMEOUT = TimeSpan.FromSeconds(2);
   private const int MAX_PARALLELISM_HTTP = 4;
diff --git a/src/Speckle.Sdk/Api/Operations/Operations.Send.cs b/src/Speckle.Sdk/Api/Operations/Operations.Send.cs
index 18ac48bb..eaad0b18 100644
--- a/src/Speckle.Sdk/Api/Operations/Operations.Send.cs
+++ b/src/Speckle.Sdk/Api/Operations/Operations.Send.cs
@@ -47,6 +47,11 @@ public partial class Operations
       receiveActivity?.SetStatus(SdkActivityStatusCode.Ok);
       return results;
     }
+    catch (OperationCanceledException)
+    {
+      //this is handled by the caller
+      throw;
+    }
     catch (Exception ex)
     {
       receiveActivity?.SetStatus(SdkActivityStatusCode.Error);
diff --git a/src/Speckle.Sdk/Serialisation/V2/Send/SerializeProcess.cs b/src/Speckle.Sdk/Serialisation/V2/Send/SerializeProcess.cs
index 0254921d..759ffa19 100644
--- a/src/Speckle.Sdk/Serialisation/V2/Send/SerializeProcess.cs
+++ b/src/Speckle.Sdk/Serialisation/V2/Send/SerializeProcess.cs
@@ -226,9 +226,17 @@ public sealed class SerializeProcess(
       var childClosures = _childClosurePool.Get();
       foreach (var childClosure in taskClosures)
       {
+        if (_processSource.Token.IsCancellationRequested)
+        {
+          return EMPTY_CLOSURES;
+        }
         foreach (var kvp in childClosure)
         {
           childClosures[kvp.Key] = kvp.Value;
+          if (_processSource.Token.IsCancellationRequested)
+          {
+            return EMPTY_CLOSURES;
+          }
         }
 
         _currentClosurePool.Return(childClosure);
@@ -253,13 +261,13 @@ public sealed class SerializeProcess(
         progress?.Report(new(ProgressEvent.FromCacheOrSerialized, _objectCount, Math.Max(_objectCount, _objectsFound)));
         foreach (var item in items)
         {
+          if (_processSource.Token.IsCancellationRequested)
+          {
+            return EMPTY_CLOSURES;
+          }
+
           if (item.NeedsStorage)
           {
-            if (_processSource.Token.IsCancellationRequested)
-            {
-              return EMPTY_CLOSURES;
-            }
-
             Interlocked.Increment(ref _objectsSerialized);
             await objectSaver.SaveAsync(item).ConfigureAwait(false);
           }