diff --git a/comfy/ldm/lightricks/vae/causal_conv3d.py b/comfy/ldm/lightricks/vae/causal_conv3d.py
index b8341edbc..356394239 100644
--- a/comfy/ldm/lightricks/vae/causal_conv3d.py
+++ b/comfy/ldm/lightricks/vae/causal_conv3d.py
@@ -65,9 +65,13 @@ class CausalConv3d(nn.Module):
             self.temporal_cache_state[tid] = (x[:, :, -(self.time_kernel_size - 1):, :, :], False)
 
         x = torch.cat(pieces, dim=2)
+        del pieces
+        del cached
 
         if needs_caching:
             self.temporal_cache_state[tid] = (x[:, :, -(self.time_kernel_size - 1):, :, :], False)
+        elif is_end:
+            self.temporal_cache_state[tid] = (None, True)
 
         return self.conv(x) if x.shape[2] >= self.time_kernel_size else x[:, :, :0, :, :]
 
diff --git a/comfy/ldm/lightricks/vae/causal_video_autoencoder.py b/comfy/ldm/lightricks/vae/causal_video_autoencoder.py
index 9f14f64a5..0504140ef 100644
--- a/comfy/ldm/lightricks/vae/causal_video_autoencoder.py
+++ b/comfy/ldm/lightricks/vae/causal_video_autoencoder.py
@@ -297,7 +297,23 @@ class Encoder(nn.Module):
                     module.temporal_cache_state.pop(tid, None)
 
 
-MAX_CHUNK_SIZE=(128 * 1024 ** 2)
+MIN_VRAM_FOR_CHUNK_SCALING = 6 * 1024 ** 3
+MAX_VRAM_FOR_CHUNK_SCALING = 24 * 1024 ** 3
+MIN_CHUNK_SIZE = 32 * 1024 ** 2
+MAX_CHUNK_SIZE = 128 * 1024 ** 2
+
+def get_max_chunk_size(device: torch.device) -> int:
+    total_memory = comfy.model_management.get_total_memory(dev=device)
+
+    if total_memory <= MIN_VRAM_FOR_CHUNK_SCALING:
+        return MIN_CHUNK_SIZE
+    if total_memory >= MAX_VRAM_FOR_CHUNK_SCALING:
+        return MAX_CHUNK_SIZE
+
+    interp = (total_memory - MIN_VRAM_FOR_CHUNK_SCALING) / (
+        MAX_VRAM_FOR_CHUNK_SCALING - MIN_VRAM_FOR_CHUNK_SCALING
+    )
+    return int(MIN_CHUNK_SIZE + interp * (MAX_CHUNK_SIZE - MIN_CHUNK_SIZE))
 
 class Decoder(nn.Module):
     r"""
@@ -525,8 +541,11 @@ class Decoder(nn.Module):
             timestep_shift_scale = ada_values.unbind(dim=1)
 
         output = []
+        max_chunk_size = get_max_chunk_size(sample.device)
 
-        def run_up(idx, sample, ended):
+        def run_up(idx, sample_ref, ended):
+            sample = sample_ref[0]
+            sample_ref[0] = None
             if idx >= len(self.up_blocks):
                 sample = self.conv_norm_out(sample)
                 if timestep_shift_scale is not None:
@@ -554,13 +573,21 @@ class Decoder(nn.Module):
                 return
 
             total_bytes = sample.numel() * sample.element_size()
-            num_chunks = (total_bytes + MAX_CHUNK_SIZE - 1) // MAX_CHUNK_SIZE
-            samples = torch.chunk(sample, chunks=num_chunks, dim=2)
+            num_chunks = (total_bytes + max_chunk_size - 1) // max_chunk_size
 
-            for chunk_idx, sample1 in enumerate(samples):
-                run_up(idx + 1, sample1, ended and chunk_idx == len(samples) - 1)
+            if num_chunks == 1:
+                # when we are not chunking, detach our x so the callee can free it as soon as they are done
+                next_sample_ref = [sample]
+                del sample
+                run_up(idx + 1, next_sample_ref, ended)
+                return
+            else:
+                samples = torch.chunk(sample, chunks=num_chunks, dim=2)
 
-        run_up(0, sample, True)
+                for chunk_idx, sample1 in enumerate(samples):
+                    run_up(idx + 1, [sample1], ended and chunk_idx == len(samples) - 1)
+
+        run_up(0, [sample], True)
         sample = torch.cat(output, dim=2)
 
         sample = unpatchify(sample, patch_size_hw=self.patch_size, patch_size_t=1)