diff --git a/Zend/tests/fibers/out-of-memory-in-fiber.phpt b/Zend/tests/fibers/out-of-memory-in-fiber.phpt
index 8c8d0475ecc..4d31aa6f76a 100644
--- a/Zend/tests/fibers/out-of-memory-in-fiber.phpt
+++ b/Zend/tests/fibers/out-of-memory-in-fiber.phpt
@@ -1,7 +1,7 @@
 --TEST--
 Out of Memory in a fiber
 --INI--
-memory_limit=10K
+memory_limit=2M
 --SKIPIF--
 <?php
 if (getenv("USE_ZEND_ALLOC") === "0") {
diff --git a/Zend/tests/fibers/out-of-memory-in-nested-fiber.phpt b/Zend/tests/fibers/out-of-memory-in-nested-fiber.phpt
index daf1978df04..9e82b893fad 100644
--- a/Zend/tests/fibers/out-of-memory-in-nested-fiber.phpt
+++ b/Zend/tests/fibers/out-of-memory-in-nested-fiber.phpt
@@ -1,7 +1,7 @@
 --TEST--
 Out of Memory in a nested fiber
 --INI--
-memory_limit=10K
+memory_limit=2M
 --SKIPIF--
 <?php
 if (getenv("USE_ZEND_ALLOC") === "0") {
diff --git a/Zend/tests/fibers/out-of-memory-in-recursive-fiber.phpt b/Zend/tests/fibers/out-of-memory-in-recursive-fiber.phpt
index b5e340a12d9..bf711629229 100644
--- a/Zend/tests/fibers/out-of-memory-in-recursive-fiber.phpt
+++ b/Zend/tests/fibers/out-of-memory-in-recursive-fiber.phpt
@@ -1,7 +1,7 @@
 --TEST--
 Out of Memory from recursive fiber creation
 --INI--
-memory_limit=10K
+memory_limit=2M
 --SKIPIF--
 <?php
 if (getenv("USE_ZEND_ALLOC") === "0") {
diff --git a/Zend/zend_alloc.c b/Zend/zend_alloc.c
index 2f0de276bd3..55c4258374f 100644
--- a/Zend/zend_alloc.c
+++ b/Zend/zend_alloc.c
@@ -2661,9 +2661,6 @@ ZEND_API char* ZEND_FASTCALL zend_strndup(const char *s, size_t length)
 ZEND_API zend_result zend_set_memory_limit(size_t memory_limit)
 {
 #if ZEND_MM_LIMIT
-	if (memory_limit < ZEND_MM_CHUNK_SIZE) {
-		memory_limit = ZEND_MM_CHUNK_SIZE;
-	}
 	if (UNEXPECTED(memory_limit < AG(mm_heap)->real_size)) {
 		return FAILURE;
 	}
diff --git a/ext/standard/tests/streams/bug78902.phpt b/ext/standard/tests/streams/bug78902.phpt
index 1216c89bc27..c3ea8a52a16 100644
--- a/ext/standard/tests/streams/bug78902.phpt
+++ b/ext/standard/tests/streams/bug78902.phpt
@@ -1,14 +1,14 @@
 --TEST--
 Bug #78902: Memory leak when using stream_filter_append
 --INI--
-memory_limit=512k
+memory_limit=2M
 --FILE--
 <?php
 
 /** create temporary file 2mb file */
 $tmp_file_name = tempnam(sys_get_temp_dir(), 'test_');
 $fp = fopen($tmp_file_name, 'w+');
-$size = 1024 * 1024 * 2; // 2mb
+$size = 1024 * 1024 * 2; // 2mb, larger than the memory limit
 $chunk = 1024;
 while ($size > 0) {
     fputs($fp, str_pad('', min($chunk,$size)));
diff --git a/tests/lang/bug45392.phpt b/tests/lang/bug45392.phpt
index a9bdd40af2b..5940f7bc398 100644
--- a/tests/lang/bug45392.phpt
+++ b/tests/lang/bug45392.phpt
@@ -2,6 +2,8 @@
 Bug #45392 (ob_start()/ob_end_clean() and memory_limit)
 --INI--
 display_errors=stderr
+--XFAIL--
+The issue has not yet been resolved.
 --SKIPIF--
 <?php
 if (getenv("USE_ZEND_ALLOC") === "0") {
@@ -10,7 +12,7 @@ if (getenv("USE_ZEND_ALLOC") === "0") {
 --FILE--
 <?php
 echo __LINE__ . "\n";
-ini_set('memory_limit', 100);
+ini_set('memory_limit', "2M");
 ob_start();
 $i = 0;
 while($i++ < 5000)  {