diff --git a/api/onnx_web/convert/diffusion/diffusion.py b/api/onnx_web/convert/diffusion/diffusion.py
index abc52578..303bb8e6 100644
--- a/api/onnx_web/convert/diffusion/diffusion.py
+++ b/api/onnx_web/convert/diffusion/diffusion.py
@@ -878,6 +878,9 @@ def convert_diffusion_diffusers_optimum(
             location=ONNX_WEIGHTS,
         )
 
+        del unet
+        run_gc()
+
     if conversion.control:
         logger.debug("converting CNet from pretrained UNet")
         cnet_path = convert_diffusion_diffusers_cnet(