diff --git a/src/clm/commands/sample_molecules_RNN.py b/src/clm/commands/sample_molecules_RNN.py
index fd9685df..2c64c7fb 100644
--- a/src/clm/commands/sample_molecules_RNN.py
+++ b/src/clm/commands/sample_molecules_RNN.py
@@ -86,6 +86,11 @@ def add_args(parser):
         action="store_true",
         help="Add descriptor in hidden and cell state",
     )
+    parser.add_argument(
+        "--preload_condition",
+        action="store_true",
+        help="Add descriptor in hidden and cell state",
+    )
     parser.add_argument(
         "--heldout_file",
         type=str,
@@ -137,6 +142,7 @@ def sample_molecules_RNN(
     conditional_dec=False,
     conditional_dec_l=True,
     conditional_h=False,
+    preload_condition=False,
     heldout_file=None,
 ):
     os.makedirs(os.path.dirname(os.path.abspath(output_file)), exist_ok=True)
@@ -294,20 +300,29 @@ def sample_molecules_RNN(
 
     # Erase file contents if there are any
     open(output_file, "w").close()
-
+    if preload_condition and  heldout_dataset is not None:
+        preload_descriptors=torch.stack([_[1] for _ in heldout_dataset], 0).to(model.device)
+        while len(preload_descriptors)<batch_size:
+            preload_descriptors=torch.cat([preload_descriptors, preload_descriptors], 0)
+        preload_descriptors=torch.stack([preload_descriptors, preload_descriptors], 0)
+        
     with tqdm(total=sample_mols) as pbar:
         for i in range(0, sample_mols, batch_size):
             n_sequences = min(batch_size, sample_mols - i)
             descriptors = None
             if heldout_dataset is not None:
                 # Use modulo to cycle through heldout_dataset
-                descriptor_indices = [
-                    (i + j) % len(heldout_dataset) for j in range(n_sequences)
-                ]
-                descriptors = torch.stack(
-                    [heldout_dataset[idx][1] for idx in descriptor_indices]
-                )
-                descriptors = descriptors.to(model.device)
+                if preload_condition:
+                    s=i%len(heldout_dataset)
+                    descriptors=preload_descriptors[s:s+n_sequences]
+                else:
+                    descriptor_indices = [
+                        (i + j) % len(heldout_dataset) for j in range(n_sequences)
+                    ]
+                    descriptors = torch.stack(
+                        [heldout_dataset[idx][1] for idx in descriptor_indices]
+                    )
+                    descriptors = descriptors.to(model.device)
             sampled_smiles, losses = model.sample(
                 descriptors=descriptors,
                 n_sequences=n_sequences,
@@ -349,4 +364,5 @@ def main(args):
         conditional_dec_l=args.conditional_dec_l,
         conditional_h=args.conditional_h,
         heldout_file=args.heldout_file,
+        preload_condition=args.preload_condition
     )
diff --git a/src/clm/commands/train_models_RNN.py b/src/clm/commands/train_models_RNN.py
index 84ace720..b932a824 100644
--- a/src/clm/commands/train_models_RNN.py
+++ b/src/clm/commands/train_models_RNN.py
@@ -81,6 +81,9 @@ def add_args(parser):
     parser.add_argument(
         "--learning_rate", type=float, help="Learning rate for the optimizer"
     )
+    parser.add_argument(
+        "--num_workers", type=int, help="number of workers for loading training data", default=3
+    )
 
     parser.add_argument(
         "--max_epochs", type=int, help="Maximum number of epochs for training"
@@ -220,6 +223,7 @@ def train_models_RNN(
     smiles_file,
     model_file,
     loss_file,
+    num_workers,
     conditional=False,
     conditional_emb=False,
     conditional_emb_l=True,
@@ -321,7 +325,7 @@ def train_models_RNN(
     logger.info(dataset.vocabulary.dictionary)
 
     loader = DataLoader(
-        dataset, batch_size=batch_size, shuffle=True, collate_fn=dataset.collate
+        dataset, batch_size=batch_size, shuffle=True, collate_fn=dataset.collate, num_workers=num_workers
     )
     optim = Adam(
         model.parameters(), betas=(0.9, 0.999), eps=1e-08, lr=learning_rate
@@ -411,4 +415,5 @@ def main(args):
         conditional_dec=args.conditional_dec,
         conditional_dec_l=args.conditional_dec_l,
         conditional_h=args.conditional_h,
+        num_workers=args.num_workers
     )