--- a/browser/components/preferences/in-content-old/advanced.xul
+++ b/browser/components/preferences/in-content-old/advanced.xul
@@ -29,20 +29,16 @@
 #endif
 
   <preference id="general.autoScroll"
               name="general.autoScroll"
               type="bool"/>
   <preference id="general.smoothScroll"
               name="general.smoothScroll"
               type="bool"/>
-  <preference id="layers.acceleration.disabled"
-              name="layers.acceleration.disabled"
-              type="bool"
-              inverted="true"/>
 #ifdef XP_WIN
   <preference id="gfx.direct2d.disabled"
               name="gfx.direct2d.disabled"
               type="bool"
               inverted="true"/>
 #endif
   <preference id="layout.spellcheckDefault"
               name="layout.spellcheckDefault"
@@ -182,20 +178,16 @@
         <checkbox id="useAutoScroll"
                   label="&useAutoScroll.label;"
                   accesskey="&useAutoScroll.accesskey;"
                   preference="general.autoScroll"/>
         <checkbox id="useSmoothScrolling"
                   label="&useSmoothScrolling.label;"
                   accesskey="&useSmoothScrolling.accesskey;"
                   preference="general.smoothScroll"/>
-        <checkbox id="allowHWAccel"
-                  label="&allowHWAccel.label;"
-                  accesskey="&allowHWAccel.accesskey;"
-                  preference="layers.acceleration.disabled"/>
         <checkbox id="checkSpelling"
                   label="&checkUserSpelling.label;"
                   accesskey="&checkUserSpelling.accesskey;"
                   onsyncfrompreference="return gAdvancedPane.readCheckSpelling();"
                   onsynctopreference="return gAdvancedPane.writeCheckSpelling();"
                   preference="layout.spellcheckDefault"/>
       </groupbox>
     </tabpanel>

--- a/browser/components/preferences/in-content-old/main.js
+++ b/browser/components/preferences/in-content-old/main.js
@@ -39,16 +39,36 @@ var gMainPane = {
         // way to get all file type association prefs. So we don't know
         // when the user will select the default.  We refresh here periodically
         // in case the default changes. On other Windows OS's defaults can also
         // be set while the prefs are open.
         window.setInterval(this.updateSetDefaultBrowser.bind(this), 1000);
       }
     }
 
+    this.buildContentProcessCountMenuList();
+    let processCountPref =
+      document.getElementById("dom.ipc.processCount");
+    processCountPref.addEventListener("change", () => {
+      this.updateDefaultPerformanceSettingsPref();
+    });
+    let accelerationPref =
+      document.getElementById("layers.acceleration.disabled");
+    accelerationPref.addEventListener("change", () => {
+      this.updateDefaultPerformanceSettingsPref();
+    });
+    this.updateDefaultPerformanceSettingsPref();
+
+    let defaultPerformancePref =
+      document.getElementById("browser.preferences.defaultPerformanceSettings.enabled");
+    defaultPerformancePref.addEventListener("change", () => {
+      this.updatePerformanceSettingsBox();
+    });
+    this.updatePerformanceSettingsBox();
+
     // set up the "use current page" label-changing listener
     this._updateUseCurrentButton();
     window.addEventListener("focus", this._updateUseCurrentButton.bind(this));
 
     this.updateBrowserStartupLastSession();
 
     if (AppConstants.platform == "win") {
       // Functionality for "Show tabs in taskbar" on Windows 7 and up.
@@ -380,16 +400,53 @@ var gMainPane = {
   /**
    * Restores the default home page as the user's home page.
    */
   restoreDefaultHomePage() {
     var homePage = document.getElementById("browser.startup.homepage");
     homePage.value = homePage.defaultValue;
   },
 
+  updateDefaultPerformanceSettingsPref() {
+    let defaultPerformancePref =
+      document.getElementById("browser.preferences.defaultPerformanceSettings.enabled");
+    let processCountPref = document.getElementById("dom.ipc.processCount");
+    let accelerationPref = document.getElementById("layers.acceleration.disabled");
+    if (processCountPref.value != processCountPref.defaultValue ||
+        accelerationPref.value != accelerationPref.defaultValue) {
+      defaultPerformancePref.value = false;
+    }
+  },
+
+  updatePerformanceSettingsBox() {
+    let defaultPerformancePref =
+      document.getElementById("browser.preferences.defaultPerformanceSettings.enabled");
+    let performanceSettings = document.getElementById("performanceSettings");
+    if (defaultPerformancePref.value) {
+      let processCountPref = document.getElementById("dom.ipc.processCount");
+      let accelerationPref = document.getElementById("layers.acceleration.disabled");
+      processCountPref.value = processCountPref.defaultValue;
+      accelerationPref.value = accelerationPref.defaultValue;
+      performanceSettings.hidden = true;
+    } else {
+      performanceSettings.hidden = false;
+    }
+  },
+
+  buildContentProcessCountMenuList() {
+    let processCountPref = document.getElementById("dom.ipc.processCount");
+    let bundlePreferences = document.getElementById("bundlePreferences");
+    let label = bundlePreferences.getFormattedString("defaultContentProcessCount",
+      [processCountPref.defaultValue]);
+    let contentProcessCount =
+      document.querySelector(`#contentProcessCount > menupopup >
+                              menuitem[value="${processCountPref.defaultValue}"]`);
+    contentProcessCount.label = label;
+  },
+
   // DOWNLOADS
 
   /*
    * Preferences:
    *
    * browser.download.useDownloadDir - bool
    *   True - Save files directly to the folder configured via the
    *   browser.download.folderList preference.

--- a/browser/components/preferences/in-content-old/main.xul
+++ b/browser/components/preferences/in-content-old/main.xul
@@ -2,16 +2,18 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 <!-- General panel -->
 
 <script type="application/javascript"
         src="chrome://browser/content/preferences/in-content-old/main.js"/>
 
+<stringbundle id="bundlePreferences" src="chrome://browser/locale/preferences.properties"/>
+
 <preferences id="mainPreferences" hidden="true" data-category="paneGeneral">
 
 #ifdef E10S_TESTING_ONLY
     <preference id="browser.tabs.remote.autostart"
                 name="browser.tabs.remote.autostart"
                 type="bool"/>
     <preference id="e10sTempPref"
                 name="browser.tabs.remote.autostart.2"
@@ -103,16 +105,29 @@
 #ifdef XP_WIN
     <preference id="browser.taskbar.previews.enable"
                 name="browser.taskbar.previews.enable"
                 type="bool"/>
 #endif
     <preference id="browser.ctrlTab.previews"
                 name="browser.ctrlTab.previews"
                 type="bool"/>
+
+  <preference id="browser.preferences.defaultPerformanceSettings.enabled"
+              name="browser.preferences.defaultPerformanceSettings.enabled"
+              type="bool"/>
+
+  <preference id="dom.ipc.processCount"
+              name="dom.ipc.processCount"
+              type="int"/>
+
+  <preference id="layers.acceleration.disabled"
+              name="layers.acceleration.disabled"
+              type="bool"
+              inverted="true"/>
 </preferences>
 
 <hbox id="header-general"
       class="header"
       hidden="true"
       data-category="paneGeneral">
   <label class="header-name" flex="1">&paneGeneral.title;</label>
   <html:a class="help-button" target="_blank" aria-label="&helpButton.label;"></html:a>
@@ -297,8 +312,41 @@
               preference="browser.tabs.loadInBackground"/>
 
 #ifdef XP_WIN
     <checkbox id="showTabsInTaskbar" label="&showTabsInTaskbar.label;"
               accesskey="&showTabsInTaskbar.accesskey;"
               preference="browser.taskbar.previews.enable"/>
 #endif
 </groupbox>
+
+<!-- Performance -->
+<groupbox id="performanceGroup" data-category="paneGeneral" hidden="true">
+  <caption><label>&performance.label;</label></caption>
+
+  <checkbox id="useRecommendedPerformanceSettings"
+            label="&useRecommendedPerformanceSettings.label;"
+            accesskey="&useRecommendedPerformanceSettings.accesskey;"
+            preference="browser.preferences.defaultPerformanceSettings.enabled"/>
+  <description class="indent">&useRecommendedPerformanceSettings.description;</description>
+
+  <vbox id="performanceSettings" class="indent" hidden="true">
+    <checkbox id="allowHWAccel"
+              label="&allowHWAccel.label;"
+              accesskey="&allowHWAccel.accesskey;"
+              preference="layers.acceleration.disabled"/>
+    <hbox align="center">
+      <label id="limitContentProcess" accesskey="&limitContentProcess.accesskey;" control="contentProcessCount">&limitContentProcess.label;</label>
+      <menulist id="contentProcessCount" preference="dom.ipc.processCount">
+        <menupopup>
+          <menuitem label="1" value="1"/>
+          <menuitem label="2" value="2"/>
+          <menuitem label="3" value="3"/>
+          <menuitem label="4" value="4"/>
+          <menuitem label="5" value="5"/>
+          <menuitem label="6" value="6"/>
+          <menuitem label="7" value="7"/>
+        </menupopup>
+      </menulist>
+    </hbox>
+    <description>&limitContentProcess.description;</description>
+  </vbox>
+</groupbox>

--- a/browser/components/preferences/in-content-old/tests/browser.ini
+++ b/browser/components/preferences/in-content-old/tests/browser.ini
@@ -25,16 +25,17 @@ skip-if = os != "win" # This test tests 
 [browser_connection.js]
 [browser_connection_bug388287.js]
 [browser_cookies_exceptions.js]
 [browser_defaultbrowser_alwayscheck.js]
 [browser_healthreport.js]
 skip-if = true || !healthreport # Bug 1185403 for the "true"
 [browser_homepages_filter_aboutpreferences.js]
 [browser_notifications_do_not_disturb.js]
+[browser_performance.js]
 [browser_permissions_urlFieldHidden.js]
 [browser_proxy_backup.js]
 [browser_privacypane_1.js]
 [browser_privacypane_3.js]
 [browser_privacypane_4.js]
 [browser_privacypane_5.js]
 [browser_privacypane_8.js]
 [browser_sanitizeOnShutdown_prefLocked.js]

new file mode 100644
--- /dev/null
+++ b/browser/components/preferences/in-content-old/tests/browser_performance.js
@@ -0,0 +1,124 @@
+const DEFAULT_HW_ACCEL_PREF = Services.prefs.getDefaultBranch(null).getBoolPref("layers.acceleration.disabled");
+const DEFAULT_PROCESS_COUNT = Services.prefs.getDefaultBranch(null).getIntPref("dom.ipc.processCount");
+
+add_task(function*() {
+  yield SpecialPowers.pushPrefEnv({set: [
+    ["layers.acceleration.disabled", DEFAULT_HW_ACCEL_PREF],
+    ["dom.ipc.processCount", DEFAULT_PROCESS_COUNT],
+    ["browser.preferences.defaultPerformanceSettings.enabled", true],
+  ]});
+});
+
+add_task(function*() {
+  let prefs = yield openPreferencesViaOpenPreferencesAPI("paneGeneral", null, {leaveOpen: true});
+  is(prefs.selectedPane, "paneGeneral", "General pane was selected");
+
+  let doc = gBrowser.selectedBrowser.contentDocument;
+  let useRecommendedPerformanceSettings = doc.querySelector("#useRecommendedPerformanceSettings");
+
+  is(Services.prefs.getBoolPref("browser.preferences.defaultPerformanceSettings.enabled"), true,
+    "pref value should be true before clicking on checkbox");
+  ok(useRecommendedPerformanceSettings.checked, "checkbox should be checked before clicking on checkbox");
+
+  useRecommendedPerformanceSettings.click();
+
+  let performanceSettings = doc.querySelector("#performanceSettings");
+  is(performanceSettings.hidden, false, "performance settings section is shown");
+
+  is(Services.prefs.getBoolPref("browser.preferences.defaultPerformanceSettings.enabled"), false,
+     "pref value should be false after clicking on checkbox");
+  ok(!useRecommendedPerformanceSettings.checked, "checkbox should not be checked after clicking on checkbox");
+
+  let allowHWAccel = doc.querySelector("#allowHWAccel");
+  let allowHWAccelPref = Services.prefs.getBoolPref("layers.acceleration.disabled");
+  is(allowHWAccelPref, DEFAULT_HW_ACCEL_PREF,
+    "pref value should be the default value before clicking on checkbox");
+  is(allowHWAccel.checked, !DEFAULT_HW_ACCEL_PREF, "checkbox should show the invert of the default value");
+
+  let contentProcessCount = doc.querySelector("#contentProcessCount");
+  is(Services.prefs.getIntPref("dom.ipc.processCount"), DEFAULT_PROCESS_COUNT, "default pref value should be default value");
+  is(contentProcessCount.selectedItem.value, DEFAULT_PROCESS_COUNT, "selected item should be the default one");
+
+  allowHWAccel.click();
+  allowHWAccelPref = Services.prefs.getBoolPref("layers.acceleration.disabled");
+  is(allowHWAccelPref, !DEFAULT_HW_ACCEL_PREF,
+    "pref value should be opposite of the default value after clicking on checkbox");
+  is(allowHWAccel.checked, !allowHWAccelPref, "checkbox should show the invert of the current value");
+
+  contentProcessCount.value = 7;
+  contentProcessCount.doCommand();
+  is(Services.prefs.getIntPref("dom.ipc.processCount"), 7, "pref value should be 7");
+  is(contentProcessCount.selectedItem.value, 7, "selected item should be 7");
+
+  allowHWAccel.click();
+  allowHWAccelPref = Services.prefs.getBoolPref("layers.acceleration.disabled");
+  is(allowHWAccelPref, DEFAULT_HW_ACCEL_PREF,
+    "pref value should be the default value after clicking on checkbox");
+  is(allowHWAccel.checked, !allowHWAccelPref, "checkbox should show the invert of the current value");
+
+  contentProcessCount.value = DEFAULT_PROCESS_COUNT;
+  contentProcessCount.doCommand();
+  is(Services.prefs.getIntPref("dom.ipc.processCount"), DEFAULT_PROCESS_COUNT, "pref value should be default value");
+  is(contentProcessCount.selectedItem.value, DEFAULT_PROCESS_COUNT, "selected item should be default one");
+
+  is(performanceSettings.hidden, false, "performance settings section should be still shown");
+
+  Services.prefs.setBoolPref("browser.preferences.defaultPerformanceSettings.enabled", true);
+  yield BrowserTestUtils.removeTab(gBrowser.selectedTab);
+});
+
+add_task(function*() {
+  let prefs = yield openPreferencesViaOpenPreferencesAPI("paneGeneral", null, {leaveOpen: true});
+  is(prefs.selectedPane, "paneGeneral", "General pane was selected");
+
+  let doc = gBrowser.contentDocument;
+  let performanceSettings = doc.querySelector("#performanceSettings");
+
+  is(performanceSettings.hidden, true, "performance settings section should not be shown");
+
+  Services.prefs.setBoolPref("browser.preferences.defaultPerformanceSettings.enabled", false);
+
+  is(performanceSettings.hidden, false, "performance settings section should be shown");
+
+  Services.prefs.setBoolPref("browser.preferences.defaultPerformanceSettings.enabled", true);
+  yield BrowserTestUtils.removeTab(gBrowser.selectedTab);
+});
+
+add_task(function*() {
+  Services.prefs.setIntPref("dom.ipc.processCount", 7);
+
+  let prefs = yield openPreferencesViaOpenPreferencesAPI("paneGeneral", null, {leaveOpen: true});
+  is(prefs.selectedPane, "paneGeneral", "General pane was selected");
+
+  let doc = gBrowser.contentDocument;
+
+  let performanceSettings = doc.querySelector("#performanceSettings");
+  is(performanceSettings.hidden, false, "performance settings section should be shown");
+
+  let contentProcessCount = doc.querySelector("#contentProcessCount");
+  is(Services.prefs.getIntPref("dom.ipc.processCount"), 7, "pref value should be 7");
+  is(contentProcessCount.selectedItem.value, 7, "selected item should be 7");
+
+  Services.prefs.setBoolPref("browser.preferences.defaultPerformanceSettings.enabled", true);
+  yield BrowserTestUtils.removeTab(gBrowser.selectedTab);
+});
+
+add_task(function*() {
+  Services.prefs.setBoolPref("layers.acceleration.disabled", true);
+
+  let prefs = yield openPreferencesViaOpenPreferencesAPI("paneGeneral", null, {leaveOpen: true});
+  is(prefs.selectedPane, "paneGeneral", "General pane was selected");
+
+  let doc = gBrowser.contentDocument;
+
+  let performanceSettings = doc.querySelector("#performanceSettings");
+  is(performanceSettings.hidden, false, "performance settings section should be shown");
+
+  let allowHWAccel = doc.querySelector("#allowHWAccel");
+  is(Services.prefs.getBoolPref("layers.acceleration.disabled"), true,
+    "pref value is false");
+  ok(!allowHWAccel.checked, "checkbox should not be checked");
+
+  Services.prefs.setBoolPref("browser.preferences.defaultPerformanceSettings.enabled", true);
+  yield BrowserTestUtils.removeTab(gBrowser.selectedTab);
+});

--- a/browser/locales/en-US/chrome/browser/preferences-old/advanced.dtd
+++ b/browser/locales/en-US/chrome/browser/preferences-old/advanced.dtd
@@ -18,18 +18,16 @@
 <!ENTITY useOnScreenKeyboard.accesskey   "k">
 
 <!ENTITY browsing.label                  "Browsing">
 
 <!ENTITY useAutoScroll.label             "Use autoscrolling">
 <!ENTITY useAutoScroll.accesskey         "a">
 <!ENTITY useSmoothScrolling.label        "Use smooth scrolling">
 <!ENTITY useSmoothScrolling.accesskey    "m">
-<!ENTITY allowHWAccel.label              "Use hardware acceleration when available">
-<!ENTITY allowHWAccel.accesskey          "r">
 <!ENTITY checkUserSpelling.label         "Check your spelling as you type">
 <!ENTITY checkUserSpelling.accesskey     "t">
 
 <!ENTITY dataChoicesTab.label            "Data Choices">
 
 <!ENTITY healthReportDesc.label          "Helps you understand your browser performance and shares data with &vendorShortName; about your browser health">
 <!ENTITY enableHealthReport.label        "Enable &brandShortName; Health Report">
 <!ENTITY enableHealthReport.accesskey    "R">
@@ -120,8 +118,22 @@
 <!ENTITY selectCerts.ask                 "Ask you every time">
 <!ENTITY selectCerts.ask.accesskey       "A">
 <!ENTITY enableOCSP.label                "Query OCSP responder servers to confirm the current validity of certificates">
 <!ENTITY enableOCSP.accesskey            "Q">
 <!ENTITY viewCerts.label                 "View Certificates">
 <!ENTITY viewCerts.accesskey             "C">
 <!ENTITY viewSecurityDevices.label       "Security Devices">
 <!ENTITY viewSecurityDevices.accesskey   "D">
+
+<!ENTITY performance.label               "Performance">
+<!ENTITY useRecommendedPerformanceSettings.label
+                                         "Use recommended performance settings">
+<!ENTITY useRecommendedPerformanceSettings.description
+                                         "These settings are tailored to your computer’s hardware and operating system.">
+<!ENTITY useRecommendedPerformanceSettings.accesskey
+                                         "U">
+<!ENTITY limitContentProcess.label       "Content process limit">
+<!ENTITY limitContentProcess.description
+                                         "Additional content processes can improve &brandShortName; performance when using multiple tabs, but will also use more memory.">
+<!ENTITY limitContentProcess.accesskey   "L">
+<!ENTITY allowHWAccel.label              "Use hardware acceleration when available">
+<!ENTITY allowHWAccel.accesskey          "r">

--- a/browser/locales/en-US/chrome/browser/preferences-old/preferences.properties
+++ b/browser/locales/en-US/chrome/browser/preferences-old/preferences.properties
@@ -249,8 +249,11 @@ removeContainerAlertTitle=Remove This Co
 
 # LOCALIZATION NOTE (removeContainerMsg): Semi-colon list of plural forms.
 # See: http://developer.mozilla.org/en/docs/Localization_and_Plurals
 # #S is the number of container tabs
 removeContainerMsg=If you remove this Container now, #S container tab will be closed. Are you sure you want to remove this Container?;If you remove this Container now, #S container tabs will be closed. Are you sure you want to remove this Container?
 
 removeContainerOkButton=Remove this Container
 removeContainerButton2=Don’t remove this Container
+
+# LOCALIZATION NOTE %S is the default value of the `dom.ipc.processCount` pref.
+defaultContentProcessCount=%S (default)