How to check graphics slowdowns with multiple windows

Graphics can feel smooth with one window open, then turn choppy when you switch between several apps or browser windows. That does not automatically mean your graphics card is failing. Other windows can use processing time, memory, or graphics resources even when you are not looking at them.

Compare the same browser test with a simple setup and with your usual windows open. The GPU Test measures shading power and fill rate at 1080p and gives a score out of 100. Use it to spot a repeatable change, not to diagnose a specific faulty part.

Compare graphics with one window and several

1. Open the GPU Test in your usual browser. Keep the computer plugged into power if you normally use it that way, and leave the display resolution and browser zoom unchanged.
2. For a baseline, close other open windows and pause video playback or downloads. Run the test three times, with a short, consistent pause between runs. Note the scores.
3. Reopen the windows you usually have when the slowdown happens. Use the same apps, tabs, and window arrangement if possible. Keep the GPU Test visible in front while the other windows remain open.
4. Run the test three more times under that setup and note each score. Compare the middle score from each group, rather than relying on one unusually high or low result.
5. If the slowdown happens only while a particular app is active, repeat the comparison with that app open by itself. This helps separate its effect from the combined load of all your windows.

Do not change power mode, browser settings, or display resolution halfway through the comparison. Those changes can affect the result and make it harder to identify what caused the difference.

What the result means

The scores stay similar with several windows open

The extra windows are not causing a clear change in this graphics workload. The stutter may be specific to one app, a video or animation, or the way windows are being drawn on your desktop. If only one program feels slow, check its own settings and whether the slowdown happens with the GPU Test closed.

The score is repeatedly lower with the other windows open

The additional workload is affecting the result. An app may be using graphics resources, or the computer may be busy with other work. This does not prove the GPU is defective. Close windows one at a time and repeat the comparison to find which one makes the biggest difference.

The score falls each time you repeat the test

A steady decline can point to heat, a power limit, or background work that continues during the test. Let the computer cool, close demanding apps, and compare again. A browser test cannot read the exact temperature of your graphics processor or confirm that a specific component is damaged.

The scores vary a lot between runs

Small changes can come from background tasks, browser scheduling, or normal test variation. Close video calls, game launchers, and other busy apps, then repeat the test under the same conditions. Treat a pattern across several runs as more useful than a single score.

How to reduce the slowdown

1. Close the busiest window first. Pause streaming video, animated pages, and large downloads, then check whether the slowdown improves. Close one item at a time so you can identify what is using resources.
2. Check for heavy background activity. On Windows 11, press Ctrl + Shift + Esc to open Task Manager and look for apps using a lot of GPU, CPU, or memory. On macOS, open Activity Monitor from Applications › Utilities and inspect the CPU and Memory tabs.
3. Connect the charger and check power mode. On Windows 11, open Settings › System › Power & battery › Power mode and try Best performance for a comparison. On a Mac laptop, open System Settings › Battery and check whether Low Power Mode is enabled. Return to your preferred setting afterward if you want longer battery life.
4. Set the graphics preference on Windows. If one app consistently causes the slowdown, open Settings › System › Display › Graphics, select the app, choose Options, and compare the available graphics preference. The choices shown depend on your computer. macOS generally manages graphics selection automatically, so it may not offer the same per-app control.
5. Restart the browser and computer. Save your work, close the browser completely, and reopen it. A restart can clear a stuck process or release resources left by a crashed window.
6. Install system and graphics updates. On Windows 11, check Settings › Windows Update and your computer maker's graphics driver updates. On macOS, check System Settings › General › Software Update. Retest after updating, since a driver or browser change can alter graphics performance.
7. Check airflow if performance drops as the computer warms up. Keep vents clear and use the computer on a firm surface. If it repeatedly slows under ordinary use, overheats, or shuts down, stop stressing it and arrange service.

When it may be a hardware or cooling problem

One lower browser score is not enough to call the GPU faulty. A hardware or cooling issue is more plausible if the computer also shows visual corruption, crashes, or repeated slowdowns across different graphics apps after updates and a restart. If the computer is under warranty, record the symptoms and contact the manufacturer before opening it. Otherwise, a repair shop can check cooling and hardware safely.

Why the other windows matter

A computer has to draw the contents of open windows and keep their apps running. Video, animation, games, and some web pages can continue using graphics resources in the background. Other windows may also use CPU time or memory, which can leave less room for the browser test. The result reflects the combined browser and computer workload, not a direct measurement of the graphics card in isolation.

Keep the test window in front during each run. Browsers may reduce activity in hidden tabs, so putting the test in the background can change what it measures.