Don't use is_bf16_supported to check for fp16 support.

comfy/model_management.py

@@ -722,10 +722,13 @@ def should_use_fp16(device=None, model_params=0, prioritize_performance=True, ma
     if is_intel_xpu():
         return True
 
-    if torch.cuda.is_bf16_supported():
+    if torch.version.hip:
         return True
 
     props = torch.cuda.get_device_properties("cuda")
+    if props.major >= 8:
+        return True
+
     if props.major < 6:
         return False