diff --git a/tests/checkasm/motion.c b/tests/checkasm/motion.c
index 0112822174..631a9ed29f 100644
--- a/tests/checkasm/motion.c
+++ b/tests/checkasm/motion.c
@@ -79,7 +79,8 @@ static void test_motion(const char *name, me_cmp_func test_func)
                 break;
             }
         }
-        // benchmark with the final value of ptr
+        // Test with a fixed offset, for benchmark stability
+        ptr = img2 + 3 * WIDTH + 3;
         bench_new(NULL, img1, ptr, WIDTH, 8);
     }
 }