diff --git a/deep_speech_2/data_utils/utility.py b/deep_speech_2/data_utils/utility.py
index 40e212c89c3977890d7dc87c5076e3b7f62bc380..123348cbc3b4ca50d58e309598f4539a39c072af 100644
--- a/deep_speech_2/data_utils/utility.py
+++ b/deep_speech_2/data_utils/utility.py
@@ -133,6 +133,7 @@ def xmap_readers_mp(mapper, reader, process_num, buffer_size, order=False):
         # start a read worker in a process
         target = order_read_worker if order else read_worker
         p = Process(target=target, args=(reader, in_queue))
+        p.daemon = True
         p.start()
 
         # start handle_workers with multiple processes
@@ -143,6 +144,7 @@ def xmap_readers_mp(mapper, reader, process_num, buffer_size, order=False):
             Process(target=target, args=args) for _ in xrange(process_num)
         ]
         for w in workers:
+            w.daemon = True
             w.start()
 
         # get results
diff --git a/deep_speech_2/examples/aishell/run_train.sh b/deep_speech_2/examples/aishell/run_train.sh
index 8e61ec3c2ad80291f7d45391f6c01c8c62a126c8..afb7d2efb2b41b6f50d95049edc0d234eadf4de1 100644
--- a/deep_speech_2/examples/aishell/run_train.sh
+++ b/deep_speech_2/examples/aishell/run_train.sh
@@ -9,7 +9,7 @@ python -u train.py \
 --batch_size=64 \
 --trainer_count=8 \
 --num_passes=50 \
---num_proc_data=12 \
+--num_proc_data=8 \
 --num_conv_layers=2 \
 --num_rnn_layers=3 \
 --rnn_layer_size=1024 \
diff --git a/deep_speech_2/examples/librispeech/run_train.sh b/deep_speech_2/examples/librispeech/run_train.sh
index 69251fe0c53c33bf8f48d2516328e74cd00e3852..073619c2ab2307c07a29e7220fca2d38ecd37120 100644
--- a/deep_speech_2/examples/librispeech/run_train.sh
+++ b/deep_speech_2/examples/librispeech/run_train.sh
@@ -9,7 +9,7 @@ python -u train.py \
 --batch_size=512 \
 --trainer_count=8 \
 --num_passes=50 \
---num_proc_data=12 \
+--num_proc_data=8 \
 --num_conv_layers=2 \
 --num_rnn_layers=3 \
 --rnn_layer_size=2048 \
diff --git a/deep_speech_2/test.py b/deep_speech_2/test.py
index 40f0795a1308d4df9287a32abb5018b099aa5935..51c725c5f76fd6b1e59d042988546b0b6934e43b 100644
--- a/deep_speech_2/test.py
+++ b/deep_speech_2/test.py
@@ -18,7 +18,7 @@ add_arg('batch_size',       int,    128,    "Minibatch size.")
 add_arg('trainer_count',    int,    8,      "# of Trainers (CPUs or GPUs).")
 add_arg('beam_size',        int,    500,    "Beam search width.")
 add_arg('num_proc_bsearch', int,    12,     "# of CPUs for beam search.")
-add_arg('num_proc_data',    int,    12,     "# of CPUs for data preprocessing.")
+add_arg('num_proc_data',    int,    4,      "# of CPUs for data preprocessing.")
 add_arg('num_conv_layers',  int,    2,      "# of convolution layers.")
 add_arg('num_rnn_layers',   int,    3,      "# of recurrent layers.")
 add_arg('rnn_layer_size',   int,    2048,   "# of recurrent cells per layer.")
diff --git a/deep_speech_2/train.py b/deep_speech_2/train.py
index 44b2ccbc46c87966461001d4a1086e0f16bbc48a..017cc73f64aaac82f176c54fb6063b6afa22e829 100644
--- a/deep_speech_2/train.py
+++ b/deep_speech_2/train.py
@@ -16,7 +16,7 @@ add_arg = functools.partial(add_arguments, argparser=parser)
 add_arg('batch_size',       int,    256,    "Minibatch size.")
 add_arg('trainer_count',    int,    8,      "# of Trainers (CPUs or GPUs).")
 add_arg('num_passes',       int,    200,    "# of training epochs.")
-add_arg('num_proc_data',    int,    12,     "# of CPUs for data preprocessing.")
+add_arg('num_proc_data',    int,    8,      "# of CPUs for data preprocessing.")
 add_arg('num_conv_layers',  int,    2,      "# of convolution layers.")
 add_arg('num_rnn_layers',   int,    3,      "# of recurrent layers.")
 add_arg('rnn_layer_size',   int,    2048,   "# of recurrent cells per layer.")