diff --git a/scripts/developer/tests/loadedMachine.js b/scripts/developer/tests/loadedMachine.js
new file mode 100644
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+++ b/scripts/developer/tests/loadedMachine.js
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+"use strict";
+/*jslint vars: true, plusplus: true*/
+/*globals Script, MyAvatar, Quat, Render, ScriptDiscoveryService, Window, LODManager, Entities, print*/
+//
+//  loadedMachine.js
+//  scripts/developer/tests/
+//
+//  Created by Howard Stearns on 6/6/16.
+//  Copyright 2016 High Fidelity, Inc.
+//
+//  Distributed under the Apache License, Version 2.0.
+//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
+//
+//  Characterises the performance of heavily loaded or struggling machines.
+//  There is no point in running this on a machine that producing the target 60 or 90 hz rendering rate.
+//
+//  The script examines several source of load, including each running script and a couple of Entity types.
+//  It turns all of these off, as well as LOD management, and twirls in place to get a baseline render rate.
+//  Then it turns each load on, one at a time, and records a new render rate.
+//  At the end, it reports the ordered results (in a popup), restores the original loads and LOD management, and quits.
+//
+//  Small performance changes are not meaningful.
+//  If you think you find something that is significant, you should probably run again to make sure that it isn't random variation.
+//  You can also compare (e.g., the baseline) for different conditions such as domain, version, server settings, etc.
+//  This does not profile scripts as they are used -- it merely measures the effect of having the script loaded and running quietly.
+
+var NUMBER_OF_TWIRLS_PER_LOAD = 10;
+var MILLISECONDS_PER_SECOND = 1000;
+var WAIT_TIME_MILLISECONDS = MILLISECONDS_PER_SECOND;
+var accumulatedRotation = 0;
+var start;
+var frames = 0;
+var config = Render.getConfig("Stats");
+var thisPath = Script.resolvePath('');
+var scriptData = ScriptDiscoveryService.getRunning();
+var scripts = scriptData.filter(function (datum) { return datum.name !== 'defaultScripts.js'; }).map(function (script) { return script.path; });
+// If defaultScripts.js is running, we leave it running, because restarting it safely is a mess.
+var otherScripts = scripts.filter(function (path) { return path !== thisPath; });
+var numberLeftRunning = scriptData.length - otherScripts.length;
+print('initially running', otherScripts.length, 'scripts. Leaving', numberLeftRunning, 'and stopping', otherScripts);
+var typedEntities = {Light: [], ParticleEffect: []};
+var interestingTypes = Object.keys(typedEntities);
+var loads = ['ignore', 'baseline'].concat(otherScripts, interestingTypes);
+var loadIndex = 0, nLoads = loads.length, load;
+var results = [];
+var initialLodIsAutomatic = LODManager.getAutomaticLODAdjust();
+var SEARCH_RADIUS = 17000;
+var DEFAULT_LOD = 32768 * 400;
+LODManager.setAutomaticLODAdjust(false);
+LODManager.setOctreeSizeScale(DEFAULT_LOD);
+
+// Fill the typedEnties with the entityIDs that are already visible. It would be nice if this were more efficient.
+var allEntities = Entities.findEntities(MyAvatar.position, SEARCH_RADIUS);
+print('Searching', allEntities.length, 'entities for', interestingTypes);
+allEntities.forEach(function (entityID) {
+    var properties = Entities.getEntityProperties(entityID, ['type', 'visible']);
+    if (properties.visible && (interestingTypes.indexOf(properties.type) >= 0)) {
+        typedEntities[properties.type].push(entityID);
+    }
+});
+interestingTypes.forEach(function (type) {
+    print('There are', typedEntities[type].length, type, 'entities.');
+});
+function toggleVisibility(type, on) {
+    typedEntities[type].forEach(function (entityID) {
+        Entities.editEntity(entityID, {visible: on});
+    });
+}
+function restoreOneTest(load) {
+    print('restore', load);
+    switch (load) {
+    case 'baseline':
+    case 'ignore':  // ignore is used to do a twirl to make sure everything is loaded.
+        break;
+    case 'Light':
+    case 'ParticleEffect':
+        toggleVisibility(load, true);
+        break;
+    default:
+        Script.load(load);
+    }
+}
+function undoOneTest(load) {
+    print('stop', load);
+    switch (load) {
+    case 'baseline':
+    case 'ignore':
+        break;
+    case 'Light':
+    case 'ParticleEffect':
+        toggleVisibility(load, false);
+        break;
+    default:
+        ScriptDiscoveryService.stopScript(load);
+    }
+}
+loads.forEach(undoOneTest);
+
+function finalReport() {
+    var baseline = results[0];
+    results.forEach(function (result) {
+        result.ratio = (baseline.fps / result.fps);
+    });
+    results.sort(function (a, b) { return b.ratio - a.ratio; });
+    var report = 'Performance Report:\nBaseline: ' + baseline.fps.toFixed(1) + ' fps.';
+    results.forEach(function (result) {
+        report += '\n' + result.ratio.toFixed(2) + ' (' + result.fps.toFixed(1) + ' fps over ' + result.elapsed + ' seconds) for ' + result.name;
+    });
+    Window.alert(report);
+    LODManager.setAutomaticLODAdjust(initialLodIsAutomatic);
+    loads.forEach(restoreOneTest);
+    Script.stop();
+}
+
+function onNewStats() { // Accumulates frames on signal during load test
+    frames++;
+}
+var DEGREES_PER_FULL_TWIRL = 360;
+var DEGREES_PER_UPDATE = 6;
+function onUpdate() { // Spins on update signal during load test
+    MyAvatar.orientation = Quat.fromPitchYawRollDegrees(0, accumulatedRotation, 0);
+    accumulatedRotation += DEGREES_PER_UPDATE;
+    if (accumulatedRotation >= (DEGREES_PER_FULL_TWIRL * NUMBER_OF_TWIRLS_PER_LOAD)) {
+        tearDown();
+    }
+}
+function startTest() {
+    print('start', load);
+    accumulatedRotation = frames = 0;
+    start = Date.now();
+    Script.update.connect(onUpdate);
+    config.newStats.connect(onNewStats);
+}
+
+function setup() {
+    if (loadIndex >= nLoads) {
+        return finalReport();
+    }
+    load = loads[loadIndex];
+    restoreOneTest(load);
+    Script.setTimeout(startTest, WAIT_TIME_MILLISECONDS);
+}
+function tearDown() {
+    var now = Date.now();
+    var elapsed = (now - start) / MILLISECONDS_PER_SECOND;
+    Script.update.disconnect(onUpdate);
+    config.newStats.disconnect(onNewStats);
+    if (load !== 'ignore') {
+        results.push({name: load, fps: frames / elapsed, elapsed: elapsed});
+    }
+    undoOneTest(load);
+    loadIndex++;
+    setup();
+}
+function waitUntilStopped() { // Wait until all the scripts have stopped
+    var count = ScriptDiscoveryService.getRunning().length;
+    if (count === numberLeftRunning) {
+        return setup();
+    }
+    print('Still', count, 'scripts running');
+    Script.setTimeout(waitUntilStopped, WAIT_TIME_MILLISECONDS);
+}
+waitUntilStopped();