diff --git a/prototype_source/fx_graph_mode_ptq_dynamic.py b/prototype_source/fx_graph_mode_ptq_dynamic.py
index a256c602c7..27a7116d52 100644
--- a/prototype_source/fx_graph_mode_ptq_dynamic.py
+++ b/prototype_source/fx_graph_mode_ptq_dynamic.py
@@ -59,6 +59,7 @@
 from io import open
 import time
 import copy
+import marshal
 
 import torch
 import torch.nn as nn
@@ -238,9 +239,9 @@ def evaluate(model_, data_source):
     .set_object_type(nn.LSTM, default_dynamic_qconfig)
     .set_object_type(nn.Linear, default_dynamic_qconfig)
 )
-# Deepcopying the original model because quantization api changes the model inplace and we want
+# Deepcopying the original using native python method marshal model because quantization api changes the model inplace and we want
 # to keep the original model for future comparison
-model_to_quantize = copy.deepcopy(model)
+model_to_quantize = marshal.loads(marshal.dumps(model))
 prepared_model = prepare_fx(model_to_quantize, qconfig_mapping, example_inputs)
 print("prepared model:", prepared_model)
 quantized_model = convert_fx(prepared_model)