How to test CPU performance after a system update

Your computer feels slower after an operating system update, or a game, browser, or work app takes longer to respond. A benchmark can show whether CPU performance changed, but one score by itself cannot prove the update caused it.

Use the Processor Test to compare single-core and all-core performance. The steps below help you make a fair comparison and rule out common causes of a lower score.

Test CPU performance after the update

1. Open the Processor Test in the same browser you used before the update, if possible.
2. Close games, video calls, downloads, and other demanding apps. Keep the computer plugged in if it is a laptop.
3. Run the single-core and all-core tests. Note both scores and the score out of 100.
4. Run the test two more times under the same conditions. Record each result rather than relying on the best score.
5. Compare the new results with a pre-update result from the same tool, device, browser, and power conditions. If you did not save an earlier score, use this run as a baseline for future checks.

A benchmark result can shift slightly between runs. For a useful comparison, look at whether the same part of the test is consistently lower, not whether one run differs by a few points. If your browser or its version changed during the update, note that too, since browser engine changes can affect benchmark results.

What the result means

Both scores are close to your earlier results

The update has not caused an obvious change in this test. A slowdown in one app may instead come from that app, its settings, a driver, or a new task running in the background. Check whether the issue happens in several programs before treating it as a CPU problem.

The single-core score is lower

Single-core performance matters for tasks that depend heavily on one processor core, including some everyday apps and parts of games. A lower result can come from power-saving settings, background work, heat, or a change in the browser. Repeat the test after the computer has finished installing updates and has been idle for a few minutes.

The all-core score is lower

The all-core test puts more sustained work on the processor. If it is repeatedly lower while the single-core score is similar, check for background tasks, power limits, or heat-related slowdown. A browser test cannot show the exact CPU temperature or diagnose a faulty processor.

The scores vary widely between runs

Something may be changing while the test runs, such as an update task, cloud sync, antivirus scan, or a changing power state. Close other work, wait for the system to settle, and run the test again. For more on inconsistent CPU results, see why CPU scores change between tests.

You do not have an earlier score

You cannot reliably reconstruct the computer's exact pre-update performance from memory. Save the current results as a reference, then compare future tests using the same setup. A current score is still useful for checking whether performance stays stable.

How to fix a lower score

1. Let updates finish. After an update, the system may still be indexing files, scanning, or completing setup tasks. On Windows 11, check Settings › Windows Update. On macOS, check System Settings › General › Software Update, then restart if an update is waiting for one.
2. Close apps using the CPU. On Windows, press Ctrl + Shift + Esc to open Task Manager and check the CPU column under Processes. On a Mac, open Activity Monitor and select the CPU view. Close only apps you recognize and do not need.
3. Use consistent power conditions. Plug in a laptop and check that it is not in a power-saving mode. In Windows 11, open Settings › System › Power & battery and check Power mode. On a Mac laptop, open System Settings › Battery and check whether Low Power Mode is enabled. Repeat the test with the same power mode as your earlier run, if known.
4. Give the computer time to cool. If the computer is hot or its fans are running hard, let it sit idle on a hard surface before testing again. A processor can reduce its speed to control heat. Do not run repeated load tests if the device is unusually hot or shutting down.
5. Restart and retest. A restart can clear a stuck process or finish applying system changes. After signing back in, wait a few minutes, close other apps, and repeat both parts of the test.
6. Check the affected app separately. If the benchmark is normal but one app still feels slow, update that app and check its own settings. If several apps remain slow, review startup apps and recent driver or security software changes.

For a closer look at background activity during a benchmark, see how to check if background apps affect CPU tests.

What a browser CPU test can tell you

The Processor Test measures how quickly your computer completes specific work in the browser and reports single-core and all-core performance, with a score out of 100. Use it to compare the same computer under similar conditions, not as a guaranteed score for every app or a direct comparison between unrelated devices.

The test cannot identify every system-level cause of a slowdown, confirm that an update damaged hardware, or report exact CPU temperatures. If scores stay much lower across repeated tests after background work and power settings are ruled out, check the computer maker's support information or ask a repair professional to investigate.