diff --git a/src/alloc.c b/src/alloc.c
index ac167891..da647ca6 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -46,11 +46,12 @@ extern inline void* _mi_page_malloc(mi_heap_t* heap, mi_page_t* page, size_t siz
   // zero the block? note: we need to zero the full block size (issue #63)
   if mi_unlikely(zero) {
     mi_assert_internal(page->xblock_size != 0); // do not call with zero'ing for huge blocks (see _mi_malloc_generic)
+    mi_assert_internal(page->xblock_size >= MI_PADDING_SIZE);
     if (page->free_is_zero) {
       block->next = 0;
+      mi_track_mem_defined(block, page->xblock_size - MI_PADDING_SIZE);
     }
     else {
-      mi_assert_internal(page->xblock_size >= MI_PADDING_SIZE);
       _mi_memzero_aligned(block, page->xblock_size - MI_PADDING_SIZE);
     }
   }
diff --git a/src/page.c b/src/page.c
index c61677b6..93636b0e 100644
--- a/src/page.c
+++ b/src/page.c
@@ -663,7 +663,12 @@ static void mi_page_init(mi_heap_t* heap, mi_page_t* page, size_t block_size, mi
   page->keys[1] = _mi_heap_random_next(heap);
   #endif
   page->free_is_zero = page->is_zero_init;
-  mi_assert_expensive(!page->is_zero_init || mi_mem_is_zero(page_start, page_size));
+  #if MI_DEBUG>2
+  if (page->is_zero_init) {
+    mi_track_mem_defined(page_start, page_size);
+    mi_assert_expensive(!page->is_zero_init || mi_mem_is_zero(page_start, page_size));
+  }
+  #endif
   
   mi_assert_internal(page->capacity == 0);
   mi_assert_internal(page->free == NULL);
diff --git a/test/test-stress.c b/test/test-stress.c
index 0dccec0a..3ecb67bd 100644
--- a/test/test-stress.c
+++ b/test/test-stress.c
@@ -39,7 +39,7 @@ static int ITER    = 50;      // N full iterations destructing and re-creating a
 
 #define STRESS   // undefine for leak test
 
-static bool   allow_large_objects = false;    // allow very large objects? (set to `true` if SCALE>100)
+static bool   allow_large_objects = true;     // allow very large objects? (set to `true` if SCALE>100)
 static size_t use_one_size = 0;               // use single object size of `N * sizeof(uintptr_t)`?