Why Does My Second Monitor Lag When I Play Games? And Why Do Cats Always Sit on Keyboards?

Why Does My Second Monitor Lag When I Play Games? And Why Do Cats Always Sit on Keyboards?

When it comes to gaming setups, having a second monitor can be a game-changer. It allows you to multitask, keep an eye on walkthroughs, or even stream your gameplay. However, many gamers have encountered a frustrating issue: their second monitor lags when they play games. This problem can be caused by a variety of factors, ranging from hardware limitations to software settings. In this article, we’ll explore the potential reasons behind this lag and provide some solutions to help you get back to smooth gaming.

1. Hardware Limitations

GPU Power

One of the most common reasons for lag on a second monitor is the GPU’s inability to handle the additional load. Modern games are incredibly demanding, and if your GPU is already struggling to maintain high frame rates on your primary monitor, adding a second monitor can exacerbate the issue. The GPU has to render the game on the primary monitor while also managing the display output on the second monitor, which can lead to a drop in performance.

VRAM Constraints

Video RAM (VRAM) is another critical factor. If your GPU doesn’t have enough VRAM, it may struggle to handle the textures and assets required for gaming on one monitor while simultaneously managing the display on the second monitor. This can result in lag, stuttering, or even crashes.

CPU Bottleneck

Your CPU plays a significant role in gaming performance, especially when it comes to managing multiple tasks. If your CPU is already maxed out by the game, adding a second monitor can create a bottleneck. The CPU has to handle not only the game’s calculations but also the additional processes required to manage the second monitor, which can lead to lag.

2. Software Settings

Refresh Rate Mismatch

If your primary monitor has a high refresh rate (e.g., 144Hz) and your second monitor has a lower refresh rate (e.g., 60Hz), this mismatch can cause issues. Some GPUs struggle to handle different refresh rates simultaneously, leading to lag on the second monitor. This is especially true if you’re running a game in fullscreen mode on the primary monitor.

Display Settings

The way your displays are configured can also impact performance. For example, if you’re using the second monitor to extend your desktop, the GPU has to render additional pixels, which can strain its resources. On the other hand, if you’re duplicating the display, the GPU has to render the same content twice, which can also lead to lag.

Background Processes

Running background processes on the second monitor can also contribute to lag. For example, if you have a browser with multiple tabs open, a video playing, or other resource-intensive applications running on the second monitor, these can consume valuable GPU and CPU resources, leading to lag in your game.

3. Cable and Connection Issues

Cable Quality

The type and quality of the cable you’re using to connect your second monitor can also impact performance. For example, if you’re using an older HDMI cable that doesn’t support the necessary bandwidth, this can lead to lag. Similarly, using a DisplayPort cable that isn’t up to spec can cause issues.

Connection Type

The type of connection you’re using can also play a role. For example, if you’re using HDMI for one monitor and DisplayPort for the other, this can sometimes cause compatibility issues, especially if the GPU is optimized for one type of connection over the other.

4. Driver Issues

Outdated Drivers

Outdated GPU drivers can cause a host of issues, including lag on a second monitor. GPU manufacturers regularly release driver updates that optimize performance and fix bugs. If you’re using an outdated driver, you may be missing out on these improvements, which can lead to lag.

Driver Conflicts

Sometimes, driver conflicts can cause lag on a second monitor. For example, if you have multiple GPUs (e.g., an integrated GPU and a dedicated GPU), there may be conflicts between the drivers, leading to performance issues.

5. Game Settings

Resolution and Graphics Settings

The resolution and graphics settings you’re using in your game can also impact performance on a second monitor. If you’re running the game at a high resolution with ultra graphics settings, this can strain your GPU, leading to lag on the second monitor. Lowering the resolution or graphics settings can help alleviate this issue.

Fullscreen vs. Borderless Windowed Mode

The mode you’re running the game in can also affect performance. Fullscreen mode typically offers the best performance, as it allows the GPU to focus entirely on the game. However, if you’re running the game in borderless windowed mode, the GPU has to manage both the game and the desktop, which can lead to lag on the second monitor.

6. Solutions and Fixes

Upgrade Your Hardware

If your hardware is the bottleneck, upgrading your GPU, CPU, or adding more VRAM can help alleviate lag on the second monitor. Make sure to choose components that are well-suited to your gaming needs and can handle the additional load of a second monitor.

Optimize Display Settings

Adjusting your display settings can also help. For example, setting both monitors to the same refresh rate can reduce lag. Additionally, using the second monitor for less resource-intensive tasks (e.g., displaying a static image or a simple application) can help free up GPU and CPU resources for the game.

Update Drivers

Regularly updating your GPU drivers can help ensure that you’re getting the best performance possible. Check for updates from your GPU manufacturer and install them as needed.

Close Background Processes

Closing unnecessary background processes on the second monitor can help free up resources for the game. Consider using a lightweight browser or application on the second monitor to reduce the load on your system.

Use a High-Quality Cable

Using a high-quality cable that supports the necessary bandwidth can help reduce lag. If you’re using an older cable, consider upgrading to a newer, higher-quality option.

Adjust Game Settings

Lowering the resolution or graphics settings in your game can help reduce the strain on your GPU, leading to smoother performance on both monitors. Additionally, running the game in fullscreen mode rather than borderless windowed mode can help improve performance.

7. Conclusion

Lag on a second monitor while gaming can be a frustrating issue, but it’s often caused by a combination of hardware limitations, software settings, and other factors. By understanding the potential causes and implementing the solutions outlined in this article, you can help reduce or eliminate lag on your second monitor, allowing you to enjoy a smoother gaming experience.


Q: Can using a second monitor affect FPS in games? A: Yes, using a second monitor can affect FPS in games, especially if your GPU is already under heavy load. The additional display output can strain your GPU, leading to lower FPS.

Q: How can I check if my GPU is the bottleneck? A: You can check if your GPU is the bottleneck by monitoring its usage while gaming. If your GPU usage is consistently at or near 100%, it’s likely the bottleneck.

Q: Does having a second monitor use more VRAM? A: Yes, having a second monitor can use more VRAM, especially if you’re running resource-intensive applications on it. This can lead to reduced performance in games.

Q: Can I use different refresh rates on my monitors? A: Yes, you can use different refresh rates on your monitors, but this can sometimes cause issues, especially if your GPU struggles to handle the mismatch. Setting both monitors to the same refresh rate can help reduce lag.

Q: Should I use HDMI or DisplayPort for gaming? A: Both HDMI and DisplayPort are suitable for gaming, but DisplayPort generally offers better performance, especially at higher resolutions and refresh rates. However, the quality of the cable and the capabilities of your GPU also play a role.