diff --git a/mps/code/apss.c b/mps/code/apss.c
index 8821542cec8..62addb81a3a 100644
--- a/mps/code/apss.c
+++ b/mps/code/apss.c
@@ -158,7 +158,7 @@ static void testInArena(mps_arena_t arena, mps_pool_debug_option_s *options)
   /* yet (MV Debug works here, because it fakes it through PoolAlloc). */
   printf("MVFF\n");
   res = stress(mps_class_mvff(), randomSizeAligned, arena,
-               (size_t)65536, (size_t)32, sizeof(void *), TRUE, TRUE, TRUE);
+               (size_t)65536, (size_t)32, MPS_PF_ALIGN, TRUE, TRUE, TRUE);
   if (res == MPS_RES_COMMIT_LIMIT) return;
   die(res, "stress MVFF");
 
diff --git a/mps/code/mpmss.c b/mps/code/mpmss.c
index 83056fce707..5a0248d7bc9 100644
--- a/mps/code/mpmss.c
+++ b/mps/code/mpmss.c
@@ -159,7 +159,7 @@ static int testInArena(mps_arena_t arena, mps_pool_debug_option_s *options)
   /* cross-segment allocation (possibly MVFF ought not to). */
   printf("MVFF\n");
   die(stress(mps_class_mvff(), randomSize8, arena,
-             (size_t)65536, (size_t)32, sizeof(void *), TRUE, TRUE, TRUE),
+             (size_t)65536, (size_t)32, MPS_PF_ALIGN, TRUE, TRUE, TRUE),
       "stress MVFF");
   printf("MV debug\n");
   die(stress(mps_class_mv_debug(), randomSize, arena,
diff --git a/mps/code/sacss.c b/mps/code/sacss.c
index 1241caff19c..360b4aec6ff 100644
--- a/mps/code/sacss.c
+++ b/mps/code/sacss.c
@@ -173,7 +173,7 @@ static int testInArena(mps_arena_t arena)
 
   printf("MVFF\n\n");
   die(stress(mps_class_mvff(), classCOUNT, classes, randomSize8, arena,
-             (size_t)65536, (size_t)32, sizeof(void *), TRUE, TRUE, TRUE),
+             (size_t)65536, (size_t)32, MPS_PF_ALIGN, TRUE, TRUE, TRUE),
       "stress MVFF");
   printf("MV debug\n\n");
   die(stress(mps_class_mv_debug(), classCOUNT, classes, randomSize8, arena,