diff --git a/src/include/collectives.h b/src/include/collectives.h
index db8fc99fd3..4f3f55bed1 100644
--- a/src/include/collectives.h
+++ b/src/include/collectives.h
@@ -110,24 +110,18 @@ extern __device__ void NCCL_ONERANK_REDUCE_NAME(PreMulSum, float)();
 extern __device__ void NCCL_ONERANK_REDUCE_NAME(PreMulSum, double)();
 
 // CHUNKSIZE must be a multiple of SLICESIZE
-//#define ALLREDUCE_SLICESTEPS (NCCL_STEPS/4)
-//#define ALLREDUCE_CHUNKSTEPS (NCCL_STEPS/2)
-//#define ALLGATHER_SLICESTEPS (NCCL_STEPS/4)
-//#define ALLGATHER_CHUNKSTEPS (NCCL_STEPS/2)
-//#define REDUCESCATTER_SLICESTEPS (NCCL_STEPS/4)
-//#define REDUCESCATTER_CHUNKSTEPS (NCCL_STEPS/2)
-#define ALLREDUCE_SLICESTEPS 2
-#define ALLREDUCE_CHUNKSTEPS 4
-#define ALLGATHER_SLICESTEPS 4
-#define ALLGATHER_CHUNKSTEPS 4
-#define REDUCESCATTER_SLICESTEPS 2
-#define REDUCESCATTER_CHUNKSTEPS 4
+#define ALLREDUCE_SLICESTEPS (NCCL_STEPS/4)
+#define ALLREDUCE_CHUNKSTEPS (NCCL_STEPS/2)
+#define ALLGATHER_SLICESTEPS (NCCL_STEPS/4)
+#define ALLGATHER_CHUNKSTEPS (NCCL_STEPS/2)
+#define REDUCESCATTER_SLICESTEPS (NCCL_STEPS/4)
+#define REDUCESCATTER_CHUNKSTEPS (NCCL_STEPS/2)
 #define BROADCAST_SLICESTEPS 1
-#define BROADCAST_CHUNKSTEPS 4
+#define BROADCAST_CHUNKSTEPS 1
 #define REDUCE_SLICESTEPS 1
-#define REDUCE_CHUNKSTEPS 4
-#define SENDRECV_SLICEFACTOR 1
-#define NCCL_MAX_SLICE_PER_CHUNK 4  // max value for CHUNKSTEPS/SLICESTEPS, must accord with above
+#define REDUCE_CHUNKSTEPS 1
+#define SENDRECV_SLICEFACTOR 4
+#define NCCL_MAX_SLICE_PER_CHUNK 2  // max value for CHUNKSTEPS/SLICESTEPS, must accord with above
 #define ALLTOALL_PIVOT_SLICESTEPS 2
 #define ALLTOALL_PIVOT_CHUNKSTEPS 4