diff --git a/invokeai/backend/model_manager/load/model_cache/model_cache_base.py b/invokeai/backend/model_manager/load/model_cache/model_cache_base.py
index eb82f87cb2..a8c2dd3e92 100644
--- a/invokeai/backend/model_manager/load/model_cache/model_cache_base.py
+++ b/invokeai/backend/model_manager/load/model_cache/model_cache_base.py
@@ -117,7 +117,7 @@ class ModelCacheBase(ABC, Generic[T]):
 
     @property
     @abstractmethod
-    def stats(self) -> CacheStats:
+    def stats(self) -> Optional[CacheStats]:
         """Return collected CacheStats object."""
         pass
 
diff --git a/invokeai/backend/model_manager/load/model_cache/model_cache_default.py b/invokeai/backend/model_manager/load/model_cache/model_cache_default.py
index 49b48f20ef..f2e0c01a94 100644
--- a/invokeai/backend/model_manager/load/model_cache/model_cache_default.py
+++ b/invokeai/backend/model_manager/load/model_cache/model_cache_default.py
@@ -326,11 +326,11 @@ class ModelCache(ModelCacheBase[AnyModel]):
                     f" {in_ram_models}/{in_vram_models}({locked_in_vram_models})"
                 )
 
-    def make_room(self, model_size: int) -> None:
+    def make_room(self, size: int) -> None:
         """Make enough room in the cache to accommodate a new model of indicated size."""
         # calculate how much memory this model will require
         # multiplier = 2 if self.precision==torch.float32 else 1
-        bytes_needed = model_size
+        bytes_needed = size
         maximum_size = self.max_cache_size * GIG  # stored in GB, convert to bytes
         current_size = self.cache_size()
 
@@ -385,7 +385,7 @@ class ModelCache(ModelCacheBase[AnyModel]):
             # 1 from onnx runtime object
             if not cache_entry.locked and refs <= (3 if "onnx" in model_key else 2):
                 self.logger.debug(
-                    f"Removing {model_key} from RAM cache to free at least {(model_size/GIG):.2f} GB (-{(cache_entry.size/GIG):.2f} GB)"
+                    f"Removing {model_key} from RAM cache to free at least {(size/GIG):.2f} GB (-{(cache_entry.size/GIG):.2f} GB)"
                 )
                 current_size -= cache_entry.size
                 models_cleared += 1