You are focused on an intense game when you notice it. Your second monitor, where you have your chat or a walkthrough open, suddenly becomes dull and dark. You press every button on the monitor itself, but it says the brightness is still maxed out. This confusing problem is not a sign of broken hardware. It is almost always a well-intentioned feature working against you. This guide will explain exactly why this happens and give you a clear, step-by-step path to stop it for good.

The Direct Answer: It’s a “Focus” Feature (And How to Find It)

Your computer and its software have a simple goal when you play a game in full screen. They want to give all possible performance and attention to that primary application. To do this, systems often activate hidden features designed to save power or reduce visual distraction. This is the core reason your second monitor dims when playing games. The feature is not in one single place. Instead, it hides in four different layers of your system, each with its own controls.

The first layer is inside the game you are playing. Some modern games include a setting specifically meant to dim background content. The second layer is within the software for your graphics card. Companies like NVIDIA and AMD build power-saving rules into their drivers. The third layer is the Windows operating system itself. Features related to color management and power plans can change how monitors behave. The fourth layer includes any extra applications you installed for controlling your displays.

This means your search is not for one setting called “dimming.” You must look for settings related to “power saving,” “focus,” “HDR,” or “variable refresh rate.” These are the terms used by different parts of your system to describe the same action. Understanding this is the key to finding the correct switch to flip.

Diagnose Your Dimming: Follow the Troubleshooting Flowchart

Before you start changing random settings, use this logical process to find the most likely cause. It will save you time and prevent confusion. Think of these questions as a series of steps that narrow down the problem.

First, ask yourself if the dimming is perfectly even across the whole second screen and only happens when a game is running. If the answer is yes, then you know the problem is linked to software, not a physical issue with the monitor. If the dimming is patchy or happens at all times, you may have a different hardware concern.

Second, immediately check the game’s own settings menu. Look under sections labeled “Graphics,” “Display,” or “Accessibility.” Search for any option named “Focused Mode,” “Background Dimming,” or “Reduce Distraction.” This is the fastest and most common fix for newer games. If you find it, your search is over.

Third, try a simple test. Change the game from “Fullscreen Exclusive” mode to “Borderless Windowed” or “Windowed Fullscreen” mode. If the dimming stops in borderless mode, the culprit is likely a setting in your graphics card driver that activates only during true fullscreen applications. This points your investigation directly to the NVIDIA Control Panel or AMD Software.

If the dimming continues even in borderless windowed mode, the cause is probably a system-wide setting in Windows or a third-party app. This diagnostic logic helps you move from the simplest check to more complex ones without guessing.

A Text-Based Decision Path

For clarity, here is the diagnostic path as a simple list of decisions. Start at number one and follow the path that matches your situation.

Step 1: Is the dimming uniform and only during games? No: Investigate monitor hardware or cable issues. Yes: Proceed to Step 2.

Step 2: Did you find a “Focused Mode” or similar setting in the game’s menus? Yes: Disable it. Problem solved. No: Proceed to Step 3.

Step 3: Does the dimming stop if you run the game in “Borderless Windowed” mode? Yes: The cause is in your GPU driver settings (see Fix Layer 2). No: The cause is likely in Windows settings or a third-party app (see Fix Layer 2 & 3).

Fix Layer 1: In-Game Settings and Fullscreen Modes

The very first place you should look for a solution is inside the game causing the problem. Game developers know that players can get distracted by bright secondary screens. Some have added features to help, but these often work too well.

The “Focused Mode” Fix

Games like Call of Duty: Modern Warfare and Valorant have explicit settings for this. In Call of Duty, it is literally called “Focused Mode” and is found in the Graphics or Interface settings. It has a slider that controls how much it dims non-focused content. If this slider is anything above zero, your second monitor will darken when the game is full screen. The solution is to move this slider all the way to zero percent. This tells the game not to interfere with your other displays.

Other games may place a similar option in an “Accessibility” menu, calling it something like “Reduce Background Distraction.” You must spend a few minutes carefully reading every option in the game’s display and graphics settings. This simple check resolves the issue for a large number of people.

Understanding Fullscreen Exclusive Mode

When you select “Fullscreen” in a game’s display options, it often means “Fullscreen Exclusive Mode” or FSE. This mode gives the game direct, sole control over your primary monitor. It is good for maximizing performance and reducing input lag. However, this direct control also allows the game and your graphics driver to make decisions about other connected displays.

The driver might think, “The user is only using one monitor for this intense application, so I will lower the power to the second one.” This is a design choice, not a bug. It explains why the problem is so specific to fullscreen gaming.

The Borderless Windowed Alternative

If you cannot find a game setting causing the dimming, try changing the game’s display mode itself. Switch from “Fullscreen” to “Borderless Windowed” or “Windowed Fullscreen.” This mode runs the game in a window that covers your entire screen, but it lets Windows manage the desktop.

Because Windows remains in control, it does not trigger the same power-saving or focus behaviors in your graphics driver. Your second monitor should stay at its normal brightness. The trade-off is that you might experience a tiny amount of extra input lag or a small performance drop, but for most players and systems, this is not noticeable. It is a very effective and simple workaround.

Fix Layer 2: GPU Driver and Operating System Controls

If the game itself is not the culprit, the next layer to investigate is the software that manages your graphics card and the core Windows system. These settings have broad control over how your monitors behave.

NVIDIA Control Panel Adjustments

If you have an NVIDIA graphics card, open the NVIDIA Control Panel. Do not rush into the 3D settings first. Go to the “Display” section on the left and click “Adjust desktop color settings.” At the top of this page, you will see a selection box for which display to modify. Make sure your second monitor is selected here.

Look under the “Apply color enhancements” section. Ensure that the “Use NVIDIA settings” option is selected. Then, check that the “Brightness” and “Contrast” sliders are where you want them, often at 50% default. Sometimes, these can get changed by profiles. Next, go to “Manage 3D settings” on the left. Look for a setting called “Power management mode.” Set this to “Prefer maximum performance.” This tells the driver not to lower power states aggressively, which can affect secondary displays.

AMD Software Adrenalin Edition Checks

For users with an AMD graphics card, open the AMD Software: Adrenalin Edition. Click on the “Gear” icon for settings and go to the “Display” tab. Here, look for an option called “Vari-Bright.” This feature dynamically adjusts brightness to save power and can cause dimming. Make sure it is turned off for your secondary monitor.

Also, explore the “Graphics” settings tab for advanced options. Similar to NVIDIA, look for any global power-saving features that might be enabled. AMD’s “Radeon Chill” or other battery-saving technologies, even on desktop PCs, can sometimes influence monitor behavior.

Windows HDR and Color Settings

This is one of the most common causes on modern versions of Windows. High Dynamic Range (HDR) manages brightness very differently than standard content. Windows can automatically turn HDR on or off for specific apps, causing a massive brightness shift.

Go to Windows Settings > System > Display. Click on your secondary monitor at the top. Scroll down and find “Use HDR.” Turn this setting off for the secondary monitor if it is not an HDR-capable screen. Even if it is, try turning it off as a test.

More importantly, scroll further to “HDR” settings. Look for “Auto HDR” and turn that off. Also, find the “SDR content brightness” slider. This slider controls how bright normal desktop apps look when HDR is active on the display. Adjusting this slider can sometimes fix a dim secondary screen.

Advanced Power Plan Settings

Windows power plans have deep settings that can affect components you would not expect. Search for “Edit power plan” in the Windows Start menu. Click on “Change advanced power settings.” A small window will open with a list of items.

Scroll down and expand the “PCI Express” section. Then expand “Link State Power Management.” Set this to “Off.” This prevents Windows from putting the PCIe bus (where your graphics card sits) into a low-power state.

Also, look for any section related to “Display” or “Monitor” in this list. Some systems have a setting that can turn off a display after a period of inactivity. Make sure these are set appropriately so Windows is not trying to turn your second monitor off while you are using it.

The Software and Hardware Wild Cards: Third-Party Apps and Connections

After checking the game, drivers, and Windows, a few other possibilities remain. These are less common but are worth investigating if the problem persists.

Third-Party Display Management Apps

Many users install software to better control their monitors. These apps can have features that conflict with gaming. The classic example is f.lux, which changes screen color temperature based on the time of day. Similar features exist in Windows itself as “Night Light.”

Other apps like Twinkle Tray, DisplayFusion, or even the utilities that come with your monitor can include automatic dimming or power-saving rules. The best test is to close these applications completely. Check your system tray (the area near the clock) for their icons, right-click, and choose exit or quit.

Then, launch your game again. If the dimming is gone, you know one of those apps was the cause. You can then reopen the app and dig through its settings to find a feature like “auto-dimming,” “fullscreen detection,” or “power saving” and disable it.

Cable and Port Considerations

While software is the cause ninety-five percent of the time, a poor physical connection can create strange behavior. A failing or low-quality cable can cause a weak signal handshake between your computer and the monitor.

This poor communication might mistakenly trigger the monitor’s own internal power-saving mode. If you have tried every software fix and the issue remains, try a different cable. If you are using HDMI, try a DisplayPort cable, or vice versa, if your hardware supports it.

Ensure you are using a certified, high-speed cable that matches the capabilities of your monitor. For high refresh rate or high-resolution monitors, an old or basic cable may not handle the data properly, leading to erratic performance that includes dimming.

3 Myths About Monitor Dimming You Can Ignore

When searching for solutions online, you will encounter many well-meaning but incorrect ideas. Let us clear up the most common myths so you can focus on what really works.

Myth 1: Your Monitor Is Dying or Defective

Reality: If your monitor works perfectly at all other times—during web browsing, watching videos, or working—and only dims during a specific action like gaming, it is almost certainly not a hardware failure. A failing monitor would show problems like persistent discoloration, permanent dark spots, flickering lines, or it would not turn on at all. The precise, software-triggered nature of the dimming points to a feature, not a fault.

Myth 2: You Need to Update Your BIOS or Perform a Risky Registry Edit

Reality: Updating your motherboard’s BIOS is a serious step that should only be done to fix specific, major system instabilities. It has no relation to how your graphics driver manages multiple monitors during a game. Similarly, editing the Windows registry is a powerful and risky action. While old forum posts might suggest a magical registry key, this is a brute-force approach for a precision problem. The real fix is almost always a normal setting in your driver or game that you can change safely.

Myth 3: There Is One Universal Fix That Works for Everyone

Reality: This problem has multiple potential causes across different layers of software. What fixes it for one person (like turning off HDR) may do nothing for another person whose issue is caused by a game’s Focused Mode. This is exactly why the diagnostic flowchart at the beginning of this guide is so important. It helps you identify which of the several universal fixes is the right one for your specific setup.

Frequently Asked Questions About Multi-Monitor Dimming

Does using a different brand or model for my second monitor make this more likely?

The brand itself does not cause the issue. However, mixing monitors with very different capabilities can make software adjustments more necessary. For example, if your primary monitor supports HDR and a high refresh rate like 144Hz, but your secondary monitor is a standard 60Hz SDR display, Windows and your GPU driver have to manage two very different profiles. This can sometimes confuse automated features like HDR switching or variable refresh rate, requiring you to manually adjust settings for consistency. The problem remains software-based, not hardware-based.

Could a faulty HDMI or DisplayPort cable cause this?

A truly faulty cable typically causes more obvious problems like a complete loss of signal, constant flickering, or sparkles and artifacts on the screen. It is a very low-probability cause for the specific symptom of uniform dimming only during games. However, as a last-resort check after exhausting all software options, trying a different, high-quality certified cable is a reasonable step. It eliminates one final variable, especially if the cable is old or was very inexpensive.

I fixed it, but the dimming came back after a driver update. Why?

This is a very common and frustrating experience. Graphics driver updates are designed to give you better performance and fix bugs. Part of this process often involves resetting all your custom settings back to their default values. When the installer applies the new driver, it overwrites the old configuration. Therefore, the power-saving or display management setting you previously disabled gets turned back on. The solution is to simply revisit the settings in your GPU control panel (or Windows) after a major driver update and re-apply your preferred configuration.

This situation is the final confirmation that your issue was always a software setting. You now know exactly where to go and what to change to restore your preferred multi-monitor experience, keeping your second screen bright and clear no matter what game you play.