diff --git a/aiter/dist/device_communicators/communicator_cuda.py b/aiter/dist/device_communicators/communicator_cuda.py
index fcc7ee05b2..c7837376c8 100644
--- a/aiter/dist/device_communicators/communicator_cuda.py
+++ b/aiter/dist/device_communicators/communicator_cuda.py
@@ -149,6 +149,8 @@ def all_reduce(
             qr_comm is not None
             and not qr_comm.disabled
             and qr_comm.should_quick_allreduce(input_)
+            and (input_.nelement() * input_.element_size()) >= 4*1024*1024 # input shape should be such that quick reduce will show benefits.
+            # input shape estimated at 2 * max concurrency for now. if performance issues, subject to change
         ):
             out = qr_comm.quick_all_reduce(input_)
             assert out is not None