diff --git a/lucene/core/src/test/org/apache/lucene/index/TestIndexWriterThreadsToSegments.java b/lucene/core/src/test/org/apache/lucene/index/TestIndexWriterThreadsToSegments.java
index 6e18635b660..72102e39304 100644
--- a/lucene/core/src/test/org/apache/lucene/index/TestIndexWriterThreadsToSegments.java
+++ b/lucene/core/src/test/org/apache/lucene/index/TestIndexWriterThreadsToSegments.java
@@ -273,7 +273,7 @@ public class TestIndexWriterThreadsToSegments extends LuceneTestCase {
   }
 
   public void testDocsStuckInRAMForever() throws Exception {
-    Directory dir = newFSDirectory(createTempDir());
+    Directory dir = newDirectory();
     IndexWriterConfig iwc = new IndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(random()));
     iwc.setRAMBufferSizeMB(.2);
     Codec codec = Codec.forName("Lucene46");
diff --git a/lucene/core/src/test/org/apache/lucene/index/TestTieredMergePolicy.java b/lucene/core/src/test/org/apache/lucene/index/TestTieredMergePolicy.java
index e4b5060e4a8..d24fd6fc9c0 100644
--- a/lucene/core/src/test/org/apache/lucene/index/TestTieredMergePolicy.java
+++ b/lucene/core/src/test/org/apache/lucene/index/TestTieredMergePolicy.java
@@ -225,7 +225,7 @@ public class TestTieredMergePolicy extends BaseMergePolicyTestCase {
     iwc.setMaxBufferedDocs(100);
     iwc.setRAMBufferSizeMB(-1);
     IndexWriter w = new IndexWriter(dir, iwc);
-    for(int i=0;i<100000;i++) {
+    for(int i=0;i<15000*RANDOM_MULTIPLIER;i++) {
       Document doc = new Document();
       doc.add(newTextField("id", random().nextLong() + "" + random().nextLong(), Field.Store.YES));
       w.addDocument(doc);