diff --git a/configs/graph_instant_ngp.yaml b/configs/graph_instant_ngp.yaml
index 0b436c830..c7a0821f0 100644
--- a/configs/graph_instant_ngp.yaml
+++ b/configs/graph_instant_ngp.yaml
@@ -4,10 +4,15 @@ defaults:
 
 method_name: instant_ngp
 data:
-  pixel_sampler:
-    num_rays_per_batch: 4096 # for training
+  dataloader_train:
+    pixel_sampler:
+      num_rays_per_batch: 8192 # for training
   dataloader_eval:
-    num_rays_per_chunk: 16384 # for evaluation
+    num_rays_per_chunk: 8192 # for evaluation
+
+viewer:
+  enable: true
+  num_rays_per_chunk: 16384
 
 graph:
   _target_: pyrad.graphs.instant_ngp.NGPGraph
diff --git a/configs/graph_mipnerf.yaml b/configs/graph_mipnerf.yaml
index ac913bd2f..3f6963031 100644
--- a/configs/graph_mipnerf.yaml
+++ b/configs/graph_mipnerf.yaml
@@ -16,3 +16,12 @@ graph:
   loss_coefficients:
     rgb_loss_coarse: 0.1
     rgb_loss_fine: 1.0
+
+data:
+  # Train dataloading.
+  dataloader_train:
+    _target_: pyrad.data.dataloader.TrainDataloader
+    image_sampler:
+      _target_: pyrad.data.image_sampler.CacheImageSampler
+      num_images_to_sample_from: 0
+      num_times_to_repeat_images: -1