diff --git a/comfy/ops.py b/comfy/ops.py
index ce132911..418d59e1 100644
--- a/comfy/ops.py
+++ b/comfy/ops.py
@@ -21,6 +21,8 @@ import comfy.model_management
 
 
 def cast_to(weight, dtype=None, device=None, non_blocking=False):
+    if (dtype is None or weight.dtype == dtype) and (device is None or weight.device == device):
+        return weight
     r = torch.empty_like(weight, dtype=dtype, device=device)
     r.copy_(weight, non_blocking=non_blocking)
     return r