diff --git a/toolkit/config_modules.py b/toolkit/config_modules.py
index 5ed490e..4c95909 100644
--- a/toolkit/config_modules.py
+++ b/toolkit/config_modules.py
@@ -977,6 +977,12 @@ class DatasetConfig:
 
         self.num_workers: int = kwargs.get('num_workers', 2)
         self.prefetch_factor: int = kwargs.get('prefetch_factor', 2)
+        # Pin DataLoader output tensors in page-locked RAM for faster CPU->GPU
+        # transfer. Off by default because page-locked RAM cannot be relocated
+        # by NVIDIA's Windows driver shared-memory VRAM-overflow fallback,
+        # which can cause severe PCIe thrashing for users at the VRAM ceiling.
+        # Opt in if you have stable VRAM headroom and want the transfer speedup.
+        self.pin_memory: bool = kwargs.get('pin_memory', False)
         self.extra_values: List[float] = kwargs.get('extra_values', [])
         self.square_crop: bool = kwargs.get('square_crop', False)
         # apply same augmentations to control images. Usually want this true unless special case
diff --git a/toolkit/data_loader.py b/toolkit/data_loader.py
index 8f6fb81..6b39e26 100644
--- a/toolkit/data_loader.py
+++ b/toolkit/data_loader.py
@@ -694,11 +694,14 @@ def get_dataloader_from_datasets(
         dataloader_kwargs['num_workers'] = dataset_config_list[0].num_workers
         dataloader_kwargs['prefetch_factor'] = dataset_config_list[0].prefetch_factor
 
-    # Enable pinned memory for faster CPU->GPU transfer when CUDA is available.
-    # pin_memory is independent of num_workers and works even with num_workers=0
-    # (the forced setting on native Windows / macOS due to dataset pickling
-    # constraints). No-op on non-CUDA backends.
-    if torch.cuda.is_available():
+    # Enable pinned memory only when explicitly opted in via dataset config and
+    # CUDA is available. pin_memory speeds up CPU->GPU transfer (helpful even at
+    # num_workers=0), but page-locked RAM cannot be relocated by NVIDIA's
+    # Windows driver shared-memory VRAM-overflow fallback, which can cause
+    # severe PCIe thrashing for users at the VRAM ceiling. Off by default; opt
+    # in via 'pin_memory: true' on the dataset config when VRAM headroom is
+    # stable.
+    if torch.cuda.is_available() and dataset_config_list[0].pin_memory:
         dataloader_kwargs['pin_memory'] = True
 
     if has_buckets: