diff --git a/tests/unit/test_umma_qk.cu b/tests/unit/test_umma_qk.cu
index 2dd9c799..a75de0d5 100644
--- a/tests/unit/test_umma_qk.cu
+++ b/tests/unit/test_umma_qk.cu
@@ -69,9 +69,9 @@ test_umma_qk_hd16(const bf16_t* q, const bf16_t* k,
     uint64_t desc_q = make_umma_desc_kmajor_none(sQ_smem, 128);
     uint64_t desc_k = make_umma_desc_kmajor_none(sK_smem, 128);
 
-    // Try different idesc values to understand the 4× factor
-    // Test 1: M=128, N=128
-    uint32_t idesc = make_idesc(128, 128);
+    // Test with different N values to understand scaling
+    // N=8 → n_dim=1
+    uint32_t idesc = make_idesc(128, 8);  // Try N=8
 
     if (tid == 0) {
         memcpy(&s_out[128], &desc_q, 8);