diff --git a/src/csharp/Grpc.IntegrationTesting/BenchmarkServiceImpl.cs b/src/csharp/Grpc.IntegrationTesting/BenchmarkServiceImpl.cs
index 47a15224f16..7e7bc713a03 100644
--- a/src/csharp/Grpc.IntegrationTesting/BenchmarkServiceImpl.cs
+++ b/src/csharp/Grpc.IntegrationTesting/BenchmarkServiceImpl.cs
@@ -46,16 +46,13 @@ namespace Grpc.Testing
     /// </summary>
     public class BenchmarkServiceImpl : BenchmarkService.IBenchmarkService
     {
-        private readonly int responseSize;
-
-        public BenchmarkServiceImpl(int responseSize)
+        public BenchmarkServiceImpl()
         {
-            this.responseSize = responseSize;
         }
 
         public Task<SimpleResponse> UnaryCall(SimpleRequest request, ServerCallContext context)
         {
-            var response = new SimpleResponse { Payload = CreateZerosPayload(responseSize) };
+            var response = new SimpleResponse { Payload = CreateZerosPayload(request.ResponseSize) };
             return Task.FromResult(response);
         }
 
@@ -63,7 +60,7 @@ namespace Grpc.Testing
         {
             await requestStream.ForEachAsync(async request =>
             {
-                var response = new SimpleResponse { Payload = CreateZerosPayload(responseSize) };
+                var response = new SimpleResponse { Payload = CreateZerosPayload(request.ResponseSize) };
                 await responseStream.WriteAsync(response);
             });
         }
diff --git a/src/csharp/Grpc.IntegrationTesting/ClientRunners.cs b/src/csharp/Grpc.IntegrationTesting/ClientRunners.cs
index 3223d0d0800..0b6a8ee6267 100644
--- a/src/csharp/Grpc.IntegrationTesting/ClientRunners.cs
+++ b/src/csharp/Grpc.IntegrationTesting/ClientRunners.cs
@@ -64,6 +64,8 @@ namespace Grpc.IntegrationTesting
             string target = config.ServerTargets.Single();
             GrpcPreconditions.CheckArgument(config.LoadParams.LoadCase == LoadParams.LoadOneofCase.ClosedLoop,
                 "Only closed loop scenario supported for C#");
+            GrpcPreconditions.CheckArgument(config.ClientType == ClientType.SYNC_CLIENT,
+                "Only sync client support for C#");
             GrpcPreconditions.CheckArgument(config.ClientChannels == 1, "ClientConfig.ClientChannels needs to be 1");
 
             if (config.OutstandingRpcsPerChannel != 0)
@@ -98,7 +100,7 @@ namespace Grpc.IntegrationTesting
             {
                 case RpcType.UNARY:
                     return new SyncUnaryClientRunner(channel,
-                        config.PayloadConfig.SimpleParams.ReqSize,
+                        config.PayloadConfig.SimpleParams,
                         config.HistogramParams);
 
                 case RpcType.STREAMING:
@@ -116,7 +118,7 @@ namespace Grpc.IntegrationTesting
         const double SecondsToNanos = 1e9;
 
         readonly Channel channel;
-        readonly int payloadSize;
+        readonly SimpleProtoParams payloadParams;
         readonly Histogram histogram;
 
         readonly BenchmarkService.IBenchmarkServiceClient client;
@@ -124,10 +126,9 @@ namespace Grpc.IntegrationTesting
         readonly CancellationTokenSource stoppedCts;
         readonly WallClockStopwatch wallClockStopwatch = new WallClockStopwatch();
         
-        public SyncUnaryClientRunner(Channel channel, int payloadSize, HistogramParams histogramParams)
+        public SyncUnaryClientRunner(Channel channel, SimpleProtoParams payloadParams, HistogramParams histogramParams)
         {
             this.channel = GrpcPreconditions.CheckNotNull(channel);
-            this.payloadSize = payloadSize;
             this.histogram = new Histogram(histogramParams.Resolution, histogramParams.MaxPossible);
 
             this.stoppedCts = new CancellationTokenSource();
@@ -161,7 +162,8 @@ namespace Grpc.IntegrationTesting
         {
             var request = new SimpleRequest
             {
-                Payload = CreateZerosPayload(payloadSize)
+                Payload = CreateZerosPayload(payloadParams.ReqSize),
+                ResponseSize = payloadParams.RespSize
             };
             var stopwatch = new Stopwatch();
 
diff --git a/src/csharp/Grpc.IntegrationTesting/ServerRunners.cs b/src/csharp/Grpc.IntegrationTesting/ServerRunners.cs
index 9f210081e78..516436ac5ac 100644
--- a/src/csharp/Grpc.IntegrationTesting/ServerRunners.cs
+++ b/src/csharp/Grpc.IntegrationTesting/ServerRunners.cs
@@ -77,11 +77,11 @@ namespace Grpc.IntegrationTesting
                 Logger.Warning("ServerConfig.CoreList is not supported for C#. Ignoring the value");
             }
 
-            // TODO: qps_driver needs to setup payload properly...
-            int responseSize = config.PayloadConfig != null ? config.PayloadConfig.SimpleParams.RespSize : 0;
+            GrpcPreconditions.CheckArgument(config.PayloadConfig == null,
+                "ServerConfig.PayloadConfig shouldn't be set for BenchmarkService based server.");
             var server = new Server
             {
-                Services = { BenchmarkService.BindService(new BenchmarkServiceImpl(responseSize)) },
+                Services = { BenchmarkService.BindService(new BenchmarkServiceImpl()) },
                 Ports = { new ServerPort("[::]", config.Port, credentials) }
             };