diff --git a/firebase-firestore/ktx/src/test/kotlin/com/google/firebase/firestore/ktx/FirestoreTests.kt b/firebase-firestore/ktx/src/test/kotlin/com/google/firebase/firestore/ktx/FirestoreTests.kt
index cb31d0b48cb..6750102f4d1 100644
--- a/firebase-firestore/ktx/src/test/kotlin/com/google/firebase/firestore/ktx/FirestoreTests.kt
+++ b/firebase-firestore/ktx/src/test/kotlin/com/google/firebase/firestore/ktx/FirestoreTests.kt
@@ -154,7 +154,7 @@ class FirestoreTests : BaseTestCase() {
     assertThat(isSslEnabled).isEqualTo(settings.isSslEnabled)
     assertThat(settings.isPersistenceEnabled).isFalse()
     assertThat(settings.cacheSettings)
-      .isEqualTo(memoryCacheSettings { setGcSettings(memoryEagerGcSettings {}) })
+      .isEqualTo(memoryCacheSettings { setGcSettings(memoryLruGcSettings {}) })
 
     val otherSettings = firestoreSettings {
       this.setLocalCacheSettings(
diff --git a/firebase-firestore/src/androidTest/java/com/google/firebase/firestore/BundleTest.java b/firebase-firestore/src/androidTest/java/com/google/firebase/firestore/BundleTest.java
index c6005d3d69c..3bdf5935fca 100644
--- a/firebase-firestore/src/androidTest/java/com/google/firebase/firestore/BundleTest.java
+++ b/firebase-firestore/src/androidTest/java/com/google/firebase/firestore/BundleTest.java
@@ -174,11 +174,14 @@ public void testLoadWithDocumentsThatAreAlreadyPulledFromBackend() throws Except
 
   @Test
   public void testLoadedDocumentsShouldNotBeGarbageCollectedRightAway() throws Exception {
-    // This test really only makes sense with memory persistence, as SQLite persistence only ever
+    // This test really only makes sense with memory eager GC, as LRU GCs
     // lazily deletes data
     db.setFirestoreSettings(
         new FirebaseFirestoreSettings.Builder()
-            .setLocalCacheSettings(MemoryCacheSettings.newBuilder().build())
+            .setLocalCacheSettings(
+                MemoryCacheSettings.newBuilder()
+                    .setGcSettings(MemoryLruGcSettings.newBuilder().build())
+                    .build())
             .build());
 
     InputStream bundle = new ByteArrayInputStream(createBundle());
diff --git a/firebase-firestore/src/androidTest/java/com/google/firebase/firestore/FirestoreTest.java b/firebase-firestore/src/androidTest/java/com/google/firebase/firestore/FirestoreTest.java
index 631dcec4dd8..6ae8eecfe4f 100644
--- a/firebase-firestore/src/androidTest/java/com/google/firebase/firestore/FirestoreTest.java
+++ b/firebase-firestore/src/androidTest/java/com/google/firebase/firestore/FirestoreTest.java
@@ -36,7 +36,6 @@
 import static org.junit.Assert.assertNotSame;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertSame;
-import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 import static org.junit.Assume.assumeTrue;
@@ -1335,8 +1334,8 @@ public void testLegacyCacheConfigForMemoryCache() {
 
     waitFor(instance.document("coll/doc").set(map("foo", "bar")));
 
-    assertThrows(
-        RuntimeException.class, () -> waitFor(instance.document("coll/doc").get(Source.CACHE)));
+    DocumentSnapshot snap = waitFor(instance.document("coll/doc").get(Source.CACHE));
+    assertEquals(map("foo", "bar"), snap.getData());
   }
 
   @Test
@@ -1363,8 +1362,8 @@ public void testNewCacheConfigForMemoryCache() {
 
     waitFor(instance.document("coll/doc").set(map("foo", "bar")));
 
-    assertThrows(
-        RuntimeException.class, () -> waitFor(instance.document("coll/doc").get(Source.CACHE)));
+    DocumentSnapshot snap = waitFor(instance.document("coll/doc").get(Source.CACHE));
+    assertEquals(map("foo", "bar"), snap.getData());
   }
 
   @Test
diff --git a/firebase-firestore/src/main/java/com/google/firebase/firestore/MemoryCacheSettings.java b/firebase-firestore/src/main/java/com/google/firebase/firestore/MemoryCacheSettings.java
index 3582557cefa..bef40c00556 100644
--- a/firebase-firestore/src/main/java/com/google/firebase/firestore/MemoryCacheSettings.java
+++ b/firebase-firestore/src/main/java/com/google/firebase/firestore/MemoryCacheSettings.java
@@ -66,7 +66,7 @@ public MemoryGarbageCollectorSettings getGarbageCollectorSettings() {
 
   /** A Builder for creating {@code MemoryCacheSettings} instance. */
   public static class Builder {
-    private MemoryGarbageCollectorSettings gcSettings = MemoryEagerGcSettings.newBuilder().build();
+    private MemoryGarbageCollectorSettings gcSettings = MemoryLruGcSettings.newBuilder().build();
 
     private Builder() {}
 
diff --git a/firebase-firestore/src/main/java/com/google/firebase/firestore/core/MemoryComponentProvider.java b/firebase-firestore/src/main/java/com/google/firebase/firestore/core/MemoryComponentProvider.java
index fc8180b6937..2665acb3c6c 100644
--- a/firebase-firestore/src/main/java/com/google/firebase/firestore/core/MemoryComponentProvider.java
+++ b/firebase-firestore/src/main/java/com/google/firebase/firestore/core/MemoryComponentProvider.java
@@ -75,7 +75,8 @@ private boolean isMemoryLruGcEnabled(FirebaseFirestoreSettings settings) {
       return memorySettings.getGarbageCollectorSettings() instanceof MemoryLruGcSettings;
     }
 
-    return false;
+    // Enabled by default.
+    return true;
   }
 
   @Override
diff --git a/firebase-firestore/src/test/java/com/google/firebase/firestore/FirebaseFirestoreSettingsTest.java b/firebase-firestore/src/test/java/com/google/firebase/firestore/FirebaseFirestoreSettingsTest.java
index afff447e99f..49a757369fe 100644
--- a/firebase-firestore/src/test/java/com/google/firebase/firestore/FirebaseFirestoreSettingsTest.java
+++ b/firebase-firestore/src/test/java/com/google/firebase/firestore/FirebaseFirestoreSettingsTest.java
@@ -62,7 +62,7 @@ public void builderConstructorShouldCopyAllValuesFromTheGivenSettings() {
     assertEquals(settings2.getHost(), "a.b.c");
     assertEquals(settings2.isSslEnabled(), false);
     assertEquals(settings2.isPersistenceEnabled(), false);
-    assertEquals(settings2.getCacheSizeBytes(), FirebaseFirestoreSettings.CACHE_SIZE_UNLIMITED);
+    assertEquals(settings2.getCacheSizeBytes(), FirebaseFirestoreSettings.DEFAULT_CACHE_SIZE_BYTES);
   }
 
   @Test
diff --git a/firebase-firestore/src/test/java/com/google/firebase/firestore/FirestoreTests.kt b/firebase-firestore/src/test/java/com/google/firebase/firestore/FirestoreTests.kt
index 35987d94f3f..608bc7284fa 100644
--- a/firebase-firestore/src/test/java/com/google/firebase/firestore/FirestoreTests.kt
+++ b/firebase-firestore/src/test/java/com/google/firebase/firestore/FirestoreTests.kt
@@ -148,7 +148,7 @@ class FirestoreTests : BaseTestCase() {
     assertThat(isSslEnabled).isEqualTo(settings.isSslEnabled)
     assertThat(settings.isPersistenceEnabled).isFalse()
     assertThat(settings.cacheSettings)
-      .isEqualTo(memoryCacheSettings { setGcSettings(memoryEagerGcSettings {}) })
+      .isEqualTo(memoryCacheSettings { setGcSettings(memoryLruGcSettings {}) })
 
     val otherSettings = firestoreSettings {
       this.setLocalCacheSettings(
diff --git a/firebase-firestore/src/test/java/com/google/firebase/firestore/ktx/FirestoreTests.kt b/firebase-firestore/src/test/java/com/google/firebase/firestore/ktx/FirestoreTests.kt
index 74ea542b22d..d5271c34d84 100644
--- a/firebase-firestore/src/test/java/com/google/firebase/firestore/ktx/FirestoreTests.kt
+++ b/firebase-firestore/src/test/java/com/google/firebase/firestore/ktx/FirestoreTests.kt
@@ -154,7 +154,7 @@ class FirestoreTests : BaseTestCase() {
     assertThat(isSslEnabled).isEqualTo(settings.isSslEnabled)
     assertThat(settings.isPersistenceEnabled).isFalse()
     assertThat(settings.cacheSettings)
-      .isEqualTo(memoryCacheSettings { setGcSettings(memoryEagerGcSettings {}) })
+      .isEqualTo(memoryCacheSettings { setGcSettings(memoryLruGcSettings {}) })
 
     val otherSettings = firestoreSettings {
       this.setLocalCacheSettings(