Fix Safari/Chrome freezing with multiple monitors on macOS

Why your browser freezes on the second monitor

You know the drill. You drag a Safari or Chrome window to your external monitor, and suddenly the whole thing locks up for five seconds. Or it stutters every time you scroll. Sometimes the cursor turns into a beach ball and you have to force quit.

This happens because modern browsers use hardware acceleration. That means they hand off graphics work to your Mac's GPU (graphics chip). On macOS, when you have two or more displays running at different refresh rates or resolutions, the GPU gets confused. The browser tries to use the wrong graphics pipeline, and it freezes.

I've seen this on MacBooks with M1, M2, and M3 chips, and on Intel Macs too. It's most common when one monitor is 60Hz and the other is 120Hz or 144Hz. But it can also happen when one is 4K and the other is 1080p.

Fix 1: Turn off hardware acceleration (30 seconds)

This is the first thing you try. It works for about 70% of people.

For Chrome:

1. Open Chrome. Click the three dots menu in the top-right corner.
2. Go to Settings.
3. Scroll down and click System on the left sidebar.
4. Look for "Use hardware acceleration when available." Turn it off.
5. Click Relaunch when Chrome asks.

For Safari:

1. Open Safari. In the top menu bar, click Safari > Settings (or Preferences on older macOS).
2. Click the Advanced tab.
3. Check the box at the bottom: "Show Develop menu in menu bar."
4. Now click the Develop menu that appears in the top bar.
5. Hover over Experimental Features.
6. Uncheck GPU Process and Metal GPU Acceleration. (If you don't see both, uncheck whichever is there.)
7. Close Safari and reopen it.

After you do this, drag your browser window to the other monitor. It should move smoothly now. If it's still freezing, move on to Fix 2.

Fix 2: Match your monitor refresh rates (5 minutes)

This fix works when the problem only happens on one monitor. Usually the one with a higher refresh rate (like 144Hz) causes the browser to freeze when the other is at 60Hz.

1. Open System Settings (or System Preferences).
2. Click Displays.
3. You'll see both monitors listed. Click on the monitor that has the higher refresh rate.
4. Look for Refresh Rate. Change it to match the other monitor. So if your external is 144Hz and your built-in is 60Hz, change the external to 60Hz.
5. Test your browser. Drag it back and forth between screens.

Did that stop the freezing? If yes, you're done. If not, change it back to the original refresh rate and try Fix 3.

Fix 3: Reset NVRAM and SMC on Intel Macs (15+ minutes)

This is for Intel Macs only. If you have an Apple Silicon Mac (M1, M2, M3), skip this step. Those chips don't have NVRAM or SMC the same way.

Reset NVRAM (non-volatile RAM):

1. Shut down your Mac completely.
2. Turn it on and immediately press and hold Option + Command + P + R.
3. Keep holding for about 20 seconds. You'll hear the startup sound twice. On a Mac with a T2 chip, hold until the Apple logo appears and disappears twice.
4. Release the keys. Your Mac will boot normally.

Reset SMC (system management controller):

This depends on your Mac model. For most MacBooks with a T2 chip (2018-2020 models):

1. Shut down your Mac.
2. Press and hold the following keys for 7 seconds: Control + Option + Shift on the left side.
3. After 7 seconds, also press and hold the power button (keep holding all four keys).
4. Hold for another 7 seconds. Then release all keys.
5. Wait a few seconds, then press the power button to turn it on.

For older Macs without a T2 chip, the steps are different. Check Apple's support page for your specific model.

After resetting both, test your browser again. If it still freezes, there's one more thing to try.

Fix 4: Create a custom scaled resolution (20 minutes)

This is the advanced fix. It forces macOS to use the same graphics settings on both displays. It worked for a user I helped last week who had a 4K LG monitor and a MacBook Pro 14-inch.

1. Go to System Settings > Displays.
2. Click the Advanced button at the bottom (if you don't see it, skip this fix).
3. Turn on Show resolutions as list.
4. Go back to the Displays main screen.
5. Click on your external monitor. You'll see a list of resolutions. Pick one that's scaled, not the default. Usually one that's slightly lower than the native resolution works. For example, if your monitor is 3840x2160, try 3008x1692 or 2560x1440.
6. Test your browser. Drag it between monitors.

If this fixes it, great. If not, you might need to use the same resolution on both monitors. That's not always practical, but it's the nuclear option.

What to do if nothing works

If you've tried all four fixes and your browser still freezes, it's probably a macOS or browser bug. Check for updates:

• Update macOS: Apple menu > System Settings > General > Software Update.
• Update your browser to the latest version.
• Try a different browser. If Chrome freezes, see if Firefox works. If Safari freezes, try Edge.

Also check if your monitor uses a DisplayPort or HDMI cable. Some cheap cables cause signal issues. Try a different cable if you have one.

One last thing: on some Macs, closing the lid (using clamshell mode) while using an external monitor triggers the freeze. Avoid that if you can.