diff --git a/hopper/tile_size.h b/hopper/tile_size.h
index 3bb67b7d56f..220ed4a3929 100644
--- a/hopper/tile_size.h
+++ b/hopper/tile_size.h
@@ -8,9 +8,9 @@
 
 constexpr int smem_estimate_bytes(int block_m, int block_n, int headdim, int headdim_v, int element_size) {
     // Double-buffer the residency for Q/K/V and the accumulators when the head/value dims are modest.
-    // For very large dimensions the single-stage SM120 pipeline only needs a single residency footprint, so
-    // avoid over-clamping by scaling the estimate down to one buffer in that regime.
-    int const buffering = (headdim + headdim_v >= 512) ? 1 : 2;
+    // Value dimensions 256+ already drive the shared-memory footprint high, so treat them like the large
+    // combined-head/value case and drop to a single buffer in that regime to avoid over-clamping.
+    int const buffering = (headdim_v >= 256 || headdim + headdim_v >= 512) ? 1 : 2;
     return buffering * (block_m + block_n) * (headdim + headdim_v) * element_size;
 }
 
diff --git a/tests/hopper/test_tile_size_shared_memory.py b/tests/hopper/test_tile_size_shared_memory.py
index 49e3fe24135..7cabd0856f9 100644
--- a/tests/hopper/test_tile_size_shared_memory.py
+++ b/tests/hopper/test_tile_size_shared_memory.py
@@ -53,7 +53,7 @@ def _load_bridge() -> ctypes.CDLL:
 
 def estimate_smem_bytes(block_m: int, block_n: int, headdim: int, headdim_v: int, element_size: int) -> int:
     # Mirror the buffering-aware estimate used in hopper/tile_size.h.
-    buffering = 1 if headdim + headdim_v >= 512 else 2
+    buffering = 1 if (headdim_v >= 256 or headdim + headdim_v >= 512) else 2
     return buffering * (block_m + block_n) * (headdim + headdim_v) * element_size