diff --git a/mlx/backend/metal/event.cpp b/mlx/backend/metal/event.cpp
index eb7f1b58a..39a49230d 100644
--- a/mlx/backend/metal/event.cpp
+++ b/mlx/backend/metal/event.cpp
@@ -14,6 +14,10 @@ Event::Event(Stream stream) : stream_(stream) {
   auto p = metal::new_scoped_memory_pool();
   event_ = std::shared_ptr<void>(
       metal::device(Device::gpu).mtl_device()->newSharedEvent(), dtor);
+  if (event_ == nullptr) {
+    throw std::runtime_error(
+        "[Event::Event] Failed to create Metal shared event.");
+  }
 }
 
 void Event::wait() {
diff --git a/mlx/transforms.cpp b/mlx/transforms.cpp
index d9e227ea3..bcf0cc09f 100644
--- a/mlx/transforms.cpp
+++ b/mlx/transforms.cpp
@@ -72,7 +72,12 @@ array eval_impl(std::vector<array> outputs, bool async) {
 
   // Stream events for synchronization after eval
   std::unordered_map<uint32_t, Event> events;
-  events.emplace(stream.index, Event{stream});
+  {
+    auto e = Event{stream};
+    e.set_value(1);
+    synchronizer.attach_event(e);
+    events.emplace(stream.index, std::move(e));
+  }
 
   {
     // Record the degree of each input
@@ -184,21 +189,26 @@ array eval_impl(std::vector<array> outputs, bool async) {
     }
   }
 
+  std::unordered_set<int> open_streams;
+
   while (!tape.empty()) {
     auto arr = std::move(tape.back());
     tape.pop_back();
 
     auto stream = arr.primitive().stream();
+    open_streams.insert(stream.index);
 
-    // Lookup corresponding event
-    auto e = events.find(stream.index);
-    if (e == events.end()) {
-      e = events.emplace(stream.index, Event{stream}).first;
-    }
-    e->second.set_value(1);
-    arr.attach_event(e->second);
-    for (auto& s : arr.siblings()) {
-      s.attach_event(e->second);
+    if (async) {
+      // Lookup corresponding event
+      auto e = events.find(stream.index);
+      if (e == events.end()) {
+        e = events.emplace(stream.index, Event{stream}).first;
+      }
+      e->second.set_value(1);
+      arr.attach_event(e->second);
+      for (auto& s : arr.siblings()) {
+        s.attach_event(e->second);
+      }
     }
 
     for (auto& in : arr.inputs()) {
@@ -227,9 +237,10 @@ array eval_impl(std::vector<array> outputs, bool async) {
         (get_active_memory() > get_memory_limit() &&
          scheduler::n_active_tasks() > 0)) {
       // Commit any open streams
-      for (auto& [_, e] : events) {
-        if (e.stream().device == Device::gpu) {
-          gpu::finalize(e.stream());
+      for (auto i : open_streams) {
+        auto s = get_stream(i);
+        if (s.device == Device::gpu) {
+          gpu::finalize(s);
         }
       }
       scheduler::wait_for_one();
@@ -263,9 +274,11 @@ array eval_impl(std::vector<array> outputs, bool async) {
   }
 
   // Signal the event in its stream
-  for (auto& [_, e] : events) {
-    auto s = e.stream();
-    e.signal(s);
+  for (auto i : open_streams) {
+    auto s = get_stream(i);
+    if (auto e = events.find(i); e != events.end()) {
+      e->second.signal(s);
+    }
     if (s.device == Device::gpu) {
       gpu::finalize(s);
     }
@@ -302,7 +315,7 @@ void eval(std::vector<array> outputs) {
     return;
   }
 
-  eval_impl(std::move(outputs), false).event().wait();
+  eval_impl(std::move(outputs), false).wait();
 }
 
 std::pair<std::vector<array>, std::vector<array>> vjp(