diff --git a/tests/unit/test_umma_qk.cu b/tests/unit/test_umma_qk.cu
index d62f472b..648618dd 100644
--- a/tests/unit/test_umma_qk.cu
+++ b/tests/unit/test_umma_qk.cu
@@ -80,7 +80,7 @@ test_umma_qk_hd16(
 
     // Zero TMEM — test with 32 columns first
     if (wid == 0) {
-        for (int col = 0; col < 32; col++) {
+        for (int col = 0; col < 2; col++) {
             tmem_store(tmem_base + col, 0, 0, 0, 0);
         }
         tmem_fence_store();