diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7a64bfa6c..924207527 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -158,6 +158,7 @@ jobs:
           pip install -e "client/[test]"
           pip install -e "server/[tensorrt]"
           pip install -e "server/[onnx]"
+          pip install -e "server/[transformers]"
           {
             pip install -e "server/[flash-attn]"
           } || {
@@ -170,6 +171,8 @@ jobs:
             -v -s -m "gpu" ./tests/test_tensorrt.py
           pytest --suppress-no-test-exit-code --cov=clip_client --cov=clip_server --cov-report=xml \
             -v -s -m "gpu" ./tests/test_simple.py
+          pytest --suppress-no-test-exit-code --cov=clip_client --cov=clip_server --cov-report=xml \
+            -v -s -m "gpu" ./tests/test_model.py
           echo "::set-output name=codecov_flag::cas"
         timeout-minutes: 30
         env:
diff --git a/server/clip_server/executors/clip_onnx.py b/server/clip_server/executors/clip_onnx.py
index bb589f912..860c5deb3 100644
--- a/server/clip_server/executors/clip_onnx.py
+++ b/server/clip_server/executors/clip_onnx.py
@@ -103,7 +103,9 @@ def __init__(
             sess_options.inter_op_num_threads = 1
             sess_options.intra_op_num_threads = max(num_threads, 1)
 
-        self._model.start_sessions(sess_options=sess_options, providers=providers)
+        self._model.start_sessions(
+            sess_options=sess_options, providers=providers, dtype=dtype
+        )
 
         if not self.tracer:
             self.tracer = NoOpTracer()
diff --git a/server/clip_server/model/clip_onnx.py b/server/clip_server/model/clip_onnx.py
index 2d61307ad..90a9c0f05 100644
--- a/server/clip_server/model/clip_onnx.py
+++ b/server/clip_server/model/clip_onnx.py
@@ -240,22 +240,6 @@ def __init__(
                         f'The given model path {model_path} should be a folder containing both '
                         f'`textual.onnx` and `visual.onnx`.'
                     )
-            if dtype == 'fp16':
-                import onnx
-                from onnxmltools.utils import float16_converter
-
-                _textual_model_fp16 = (
-                    float16_converter.convert_float_to_float16_model_path(
-                        self._textual_path
-                    )
-                )
-                _visual_model_fp16 = (
-                    float16_converter.convert_float_to_float16_model_path(
-                        self._visual_path
-                    )
-                )
-                onnx.save_model(_textual_model_fp16, self._textual_path)
-                onnx.save_model(_visual_model_fp16, self._visual_path)
         else:
             raise RuntimeError(
                 'CLIP model {} not found or not supports ONNX backend; below is a list of all available models:\n{}'.format(
@@ -279,33 +263,39 @@ def get_model_name(name: str):
 
     def start_sessions(
         self,
+        dtype,
         **kwargs,
     ):
         import onnxruntime as ort
 
-        def _load_session_from_zip(model_path: str, model_type: str):
-            """Load a model from a zip file."""
-            import zipfile
-            import tempfile
+        def _load_session(model_path: str, model_type: str, dtype: str):
+            if model_path.endswith('.zip') or dtype == 'fp16':
+                import tempfile
 
-            with zipfile.ZipFile(
-                model_path, 'r'
-            ) as zip_ref, tempfile.TemporaryDirectory() as tmp_dir:
-                zip_ref.extractall(tmp_dir)
-                return ort.InferenceSession(tmp_dir + f'/{model_type}.onnx', **kwargs)
+                with tempfile.TemporaryDirectory() as tmp_dir:
+                    tmp_model_path = tmp_dir + f'/{model_type}.onnx'
+                    if model_path.endswith('.zip'):
+                        import zipfile
 
-        if self._visual_path.endswith('.zip'):
-            self._visual_session = _load_session_from_zip(self._visual_path, 'visual')
-        else:
-            self._visual_session = ort.InferenceSession(self._visual_path, **kwargs)
-        self._visual_session.disable_fallback()
+                        with zipfile.ZipFile(model_path, 'r') as zip_ref:
+                            zip_ref.extractall(tmp_dir)
+                            model_path = tmp_model_path
+                    if dtype == 'fp16':
+                        import onnx
+                        from onnxmltools.utils import float16_converter
 
-        if self._textual_path.endswith('.zip'):
-            self._textual_session = _load_session_from_zip(
-                self._textual_path, 'textual'
-            )
-        else:
-            self._textual_session = ort.InferenceSession(self._textual_path, **kwargs)
+                        model_fp16 = (
+                            float16_converter.convert_float_to_float16_model_path(
+                                model_path
+                            )
+                        )
+                        onnx.save_model(model_fp16, tmp_model_path)
+                    return ort.InferenceSession(tmp_model_path, **kwargs)
+            return ort.InferenceSession(model_path, **kwargs)
+
+        self._visual_session = _load_session(self._visual_path, 'visual', dtype)
+        self._textual_session = _load_session(self._textual_path, 'textual', dtype)
+        self._visual_session.disable_fallback()
         self._textual_session.disable_fallback()
 
     def encode_image(self, image_input: Dict):
diff --git a/tests/test_model.py b/tests/test_model.py
index 053a1d2b0..f7e44177b 100644
--- a/tests/test_model.py
+++ b/tests/test_model.py
@@ -29,3 +29,14 @@ def test_torch_model(name, model_cls):
 )
 def test_onnx_model(name):
     CLIPOnnxModel(name)
+
+
+@pytest.mark.gpu
+@pytest.mark.parametrize(
+    'name',
+    ['ViT-H-14::laion2b-s32b-b79k'],
+)
+def test_large_onnx_model_fp16(name):
+    from clip_server.executors.clip_onnx import CLIPEncoder
+
+    CLIPEncoder(name, dtype='fp16')