Quick fixes to "Webpage using significant energy" error

Safari tabs are an invaluable feature, helping make the browsing experience more organized and enjoyable. However, over time, it commonly ends in having dozens of them open at once. Some people today pay a lot extra for powerful rigs with the only goal of supporting their 100+ tab habit. If only we'd known the toll it would take on our computer.

Each app and process uses memory — RAM — to quickly access the data that the system utilizes to run properly. So, if Safari exceeds the limit due to having too many tabs open or even just a few tabs with websites that are continuously refreshing and loading up new scripts and content, you'll see one of the following error messages based on the macOS version: 

  • This webpage is using significant energy. Closing it may improve the responsiveness of your Mac.
  • This webpage is using significant memory.
  • This webpage was reloaded because it was using significant energy.

Luckily, although annoying, this issue is not dangerous and can be fixed quickly. We'll show you how, so let's go.

How to get rid of the "webpage using significant memory" message

There are several fixes that will help you get rid of the issue. 

1. Restart Safari

Because the error message pops up when Safari uses too many system resources, the first thing to do is simply restart Safari. To do that, go to Safari in the menu bar and then select Quit Safari, or use the shortcut ⌘ + Q. 

2. Empty Safari's cache and cookies

Like any other browser, Safari accumulates lots of information about the websites you visit and the information you share. All this is recorded in your cache and cookies, which might become too power-taxing over time.

To clean your cache in Safari: 

  1. Go to Safari > Settings in the menu bar (or use ⌘ + ,).
  2. Navigate to the Advanced tab and select the box "Show Develop menu in menu bar."
  3. Now go to the Develop menu in the Menu bar and click Empty Caches.
  4. Restart Safari to make sure the cache is clear.

In addition, it could be beneficial to delete your cookies:

  1. Open Settings once again.
  2. Go to the Privacy tab > Manage Website Data.
  3. Press ⌘ + A to select all fields.
  4. Remove All.

Your Safari experience should become faster now, so the "This website is using significant energy." error might already be gone. 


If you don't want to clear caches manually, I have a ready-to-use recommendation for you. Just use CleanMyMac X, and the app will do everything for you. It can clear caches in all browsers at once in a matter of seconds. 

To clear caches, follow these steps:  

  • Open CleanMyMac X (download it for free here).
  • Go to System Junk. 
  • Click Scan. 
  • The app will detect all of the junk files your system stores and offer the Clean option after the scan is complete.
  • CleanMyMac X - System Junk

3. Free up RAM for a faster system

Safari is showing you the "This website is using significant energy." error because it has consumed all the available RAM. But other apps use RAM too. So freeing up that memory will give Safari more resources to utilize.

How do you free up RAM? Restarting your Mac is a quick but not a long-term solution. For immediate effect, you need to use a special tool like CleanMyMac X.

CleanMyMac X is a Swiss-knife utility designed to optimize all areas of your Mac. And resetting your RAM with it just takes a few clicks:

  1. Download CleanMyMac X for free.
  2. Open the app and navigate to the Maintenance tab under Speed.
  3. Click Free Up RAM and then Run.

This app is notarized by Apple, so you know it's a safe option to try in this case.

4. Turn off all Safari extensions

Another power-hogging aspect of any browser is its extensions. So, disabling them might actually help with the problem, especially if you have lots going on at the same time.

To turn off Safari extensions:

  1. Fire up Settings (⌘ + ,).
  2. Go to Extensions.
  3. Deselect all boxes to disable your extensions.
  4. Restart Safari to see if the error has disappeared.

Bonus: You can try turning extensions on one by one to see which of them really needs too much power.

5. Close all tabs

Another effective solution is to close all tabs. If you don't want to lose some important information, you can simply decrease the number of tabs by using the ⌘ + W shortcut. 


The problem is often site-specific. So deciding which tabs close, start with online editors or streaming websites because they use lots of RAM.

6. Check for mining scripts

Some cryptocurrency miners are lucrative enough to spread their demands to hundreds of internet users out there. Bad actors infect some websites with notorious scripts. They cannot affect your system significantly, but they may consume its resources. Note that, for some websites, such as online tools or online editors, high energy use is normal. But if you see this message while surfing a supposedly normal website, check if it does not use mining scripts. AdBlock extension for Safari helps detect them. So you'd better keep it installed and disable other extensions.

7. Update macOS

Newer OS versions offer more tools for better performance and improved resource management. If you have not updated macOS for a while, it may be a step you need to take. The best practice is to install the newest macOS updates. In most cases, they will include bug fixes, but Safari updates may come in the package.

To do it, follow these steps:

  1. Go to Apple menu in the upper left corner of the screen.
  2. Navigate to System Settings > General.
  3. Open Software Update.
  4. Click Upgrade Now if new macOS versions are available.
System Preferences - Software Update

Bonus tip: optimize your Mac

It's likely that the "significant energy" message is now gone. However, it's good to make sure it doesn't appear again by optimizing the apps that use a lot of memory and processing power.

CleanMyMac X will help you here as well:

  1. Get the app for free here.
  2. Open and go to the Optimization tab.
  3. Click on Heavy Consumers, select all the apps listed, and then click Perform.
  4. Choose one from the list and hit Quit.

At last, your Mac is fully optimized with a little help from CleanMyMac X🙂 In fact, using this or similar Mac optimization app, you can skip all the manual steps of clearing your cache files and cookies and turning off extensions and simply let the program to do the work for you in just a few seconds. 

Laptop with CleanMyMac
CleanMyMac X

Your Mac. As good as new.