diff --git a/karma-dart-evalcache.js b/karma-dart-evalcache.js
new file mode 100644
index 0000000000..7caa8a13ec
--- /dev/null
+++ b/karma-dart-evalcache.js
@@ -0,0 +1,86 @@
+// This module provides a customFileHandler for karma
+// that serves files with urls like /packages_<timestamp>/...
+// with maximum cache.
+// We are using these urls when we spawn isolates
+// so that the isolates don't reload files every time.
+
+var common = require('karma/lib/middleware/common');
+var fs = require('fs');
+
+var DART_EVAL_PATH_RE = /.*\/packages_\d+\/(.*)$/;
+
+module.exports = createFactory;
+
+function createFactory(proxyPaths) {
+  return {
+    'framework:dart-evalcache': ['factory', dartEvalCacheFactory]
+  };
+
+  function dartEvalCacheFactory(emitter, logger, customFileHandlers) {
+    var filesPromise = new common.PromiseContainer();
+    emitter.on('file_list_modified', function(files) {
+      filesPromise.set(files);
+    });
+
+    var serveFile = common.createServeFile(fs);
+    var log = logger.create('dart-evalcache');
+
+    customFileHandlers.push({
+      urlRegex: DART_EVAL_PATH_RE,
+      handler: handler
+    });
+
+    // See source_files handler
+    function handler(request, response, fa, fb, basePath) {
+      return filesPromise.then(function(files) {
+        try {
+          var requestedFilePath = mapUrlToFile(request.url, proxyPaths, basePath, log);
+          // TODO(vojta): change served to be a map rather then an array
+          var file = findByPath(files.served, requestedFilePath);
+          if (file) {
+            serveFile(file.contentPath || file.path, response, function() {
+              common.setHeavyCacheHeaders(response);
+            }, file.content);
+          } else {
+            response.writeHead(404);
+            response.end('Not found');
+          }
+        } catch (e) {
+          log.error(e.stack);
+          response.writeHead(500);
+          response.end('Error', e.stack);
+        }
+      });
+    }
+  };
+}
+
+function mapUrlToFile(url, proxyPaths, basePath, log) {
+  var originalUrl = url;
+  url = url.indexOf('?') > -1 ? url.substring(0, url.indexOf('?')) : url;
+  var match = DART_EVAL_PATH_RE.exec(url);
+  var packagePath = match[1];
+  var result = null;
+  var lastProxyFromLength = 0;
+  Object.keys(proxyPaths).forEach(function(proxyFrom) {
+    if (startsWith(packagePath, proxyFrom) && proxyFrom.length > lastProxyFromLength) {
+      lastProxyFromLength = proxyFrom.length;
+      result = proxyPaths[proxyFrom] + packagePath.substring(proxyFrom.length);
+    }
+  });
+  return basePath + '/' + result;
+}
+
+function startsWith(string, subString) {
+  return string.length >= subString.length && string.slice(0, subString.length) === subString;
+}
+
+function findByPath(files, path) {
+  for (var i = 0; i < files.length; i++) {
+    if (files[i].path === path) {
+      return files[i];
+    }
+  }
+
+  return null;
+}
diff --git a/karma-dart.conf.js b/karma-dart.conf.js
index dd72ddf51e..307c710b41 100644
--- a/karma-dart.conf.js
+++ b/karma-dart.conf.js
@@ -1,11 +1,41 @@
 var sauceConf = require('./sauce.conf');
 
+var packageSources = {
+  // Dependencies installed with `pub install`.
+  'unittest': 'packages/unittest',
+  'guinness': 'packages/guinness',
+  'matcher': 'packages/matcher',
+  'stack_trace': 'packages/stack_trace',
+  'collection': 'packages/collection',
+  'path': 'packages/path',
+  'observe': 'packages/observe',
+  'quiver': 'packages/quiver',
+  'intl': 'packages/intl',
+  'smoke': 'packages/smoke',
+  'logging': 'packages/logging',
+  'utf': 'packages/utf',
+
+  // Local dependencies, transpiled from the source.
+  'angular2/test/': 'dist/dart/angular2/test/',
+  'angular2': 'dist/dart/angular2/lib',
+  'http': 'dist/dart/http/lib',
+  'angular2_material': 'dist/dart/angular2_material/lib',
+  'benchpress': 'dist/dart/benchpress/lib',
+  'examples': 'dist/dart/examples/lib'
+};
+
+var proxyPaths = {};
+Object.keys(packageSources).map(function(packageName) {
+  var filePath = packageSources[packageName];
+  proxyPaths['/packages/'+packageName] = '/base/'+filePath;
+});
+
 // Karma configuration
 // Generated on Thu Sep 25 2014 11:52:02 GMT-0700 (PDT)
 module.exports = function(config) {
   config.set({
 
-    frameworks: ['dart-unittest'],
+    frameworks: ['dart-unittest', 'dart-evalcache'],
 
     files: [
       // Init and configure guiness.
@@ -35,27 +65,18 @@ module.exports = function(config) {
     },
 
     // Map packages to the correct urls where Karma serves them.
-    proxies: {
-      // Dependencies installed with `pub install`.
-      '/packages/unittest': '/base/packages/unittest',
-      '/packages/guinness': '/base/packages/guinness',
-      '/packages/matcher': '/base/packages/matcher',
-      '/packages/stack_trace': '/base/packages/stack_trace',
-      '/packages/collection': '/base/packages/collection',
-      '/packages/path': '/base/packages/path',
-
-      // Local dependencies, transpiled from the source.
-      '/packages/angular2/test/': '/base/dist/dart/angular2/test/',
-      '/packages/angular2': '/base/dist/dart/angular2/lib',
-      '/packages/http': '/base/dist/dart/http/lib',
-      '/packages/angular2_material': '/base/dist/dart/angular2_material/lib',
-      '/packages/benchpress': '/base/dist/dart/benchpress/lib',
-      '/packages/examples': '/base/dist/dart/examples/lib'
-    },
+    proxies: proxyPaths,
 
     customLaunchers: sauceConf.customLaunchers,
     browsers: ['DartiumWithWebPlatform'],
 
-    port: 9877
+    port: 9877,
+
+    plugins: [
+      require('karma-dart'),
+      require('karma-chrome-launcher'),
+      require('karma-sauce-launcher'),
+      require('./karma-dart-evalcache')(packageSources)
+    ]
   });
 };
diff --git a/modules/angular2/test/compiler/eval_module.dart b/modules/angular2/test/compiler/eval_module.dart
index e555b2b5ee..d2bf8b920d 100644
--- a/modules/angular2/test/compiler/eval_module.dart
+++ b/modules/angular2/test/compiler/eval_module.dart
@@ -13,7 +13,7 @@ createIsolateSource(String moduleSource, List<List<String>> moduleImports) {
     String modAlias = sourceImport[1];
     moduleSourceParts.add("import 'package:${modName}.dart' as ${modAlias};");
   });
-  moduleSourceParts.add(moduleSource);
+  moduleSourceParts.add(moduleSource); 
   
   return """
 import "dart:isolate";
@@ -26,6 +26,8 @@ main(List args, SendPort replyPort) {
 
 } 
 
+var timeStamp = new DateTime.now().millisecondsSinceEpoch;
+
 dynamic callModule(dynamic data) { return data.map( (a) => a+1); }
 
 evalModule(String moduleSource, List<List<String>> moduleImports, List args) {
@@ -36,7 +38,11 @@ evalModule(String moduleSource, List<List<String>> moduleImports, List args) {
       receivePort.close();
       completer.complete(message);
     });
-    var packageRoot = Uri.parse('/packages');
+    // Note: we have a special karma plugin that sends files under
+    // urls like /package_1234 as permanently cached.
+    // With this, spawning multiple isolates gets faster as Darts does not
+    // reload the files from the server.
+    var packageRoot = Uri.parse('/packages_${timeStamp}');
     return Isolate.spawnUri(toDartDataUri(source), args, receivePort.sendPort, packageRoot: packageRoot).then( (isolate) { 
       RawReceivePort errorPort;
       errorPort = new RawReceivePort( (message) {