Compare browser CPU speed in two power plans

Your laptop feels faster when it is plugged in, or a power-saving setting seems to slow down a task. A browser CPU test can show whether the processor scores differently in two power modes, but the comparison only means something if the conditions stay the same.

Use the Processor Test to compare its single-core and all-core results. It gives each run a score out of 100. That score is useful for comparing this computer with itself, not as a direct measure of every app's speed.

Compare the two power plans

1. Open the Processor Test in the browser you will use for both plans. Keep the tab open, and note the current power mode and whether the computer is plugged in.
2. Choose a consistent setup. For a laptop, plug in the charger for both sets of runs, or test on battery for both. Close video, game, and other CPU-heavy tasks, and avoid changing browser settings between runs.
3. Run the test in your first power plan. Record both the single-core and all-core scores, along with the plan name. Wait briefly for the computer to cool before starting another run.
4. Switch to the second plan and give the computer a minute to settle. Run the test and record both scores again under the same conditions.
5. Repeat each plan at least three times. Alternate between plans if convenient, for example A, B, A, B, so a gradual change in room temperature or computer heat is less likely to favor one plan.

Use the same browser, computer position, charger, and test tab for every run. Write down the results rather than relying on memory. If the first run after switching plans is unusually high or low, include another run before drawing a conclusion.

What the result means

Both scores are consistently higher in one plan

If repeated runs in one plan are higher by more than the ordinary variation between runs, that plan is likely letting the processor work faster for this browser test. A higher all-core score can matter for work that uses several processor cores at once. A higher single-core score may be more relevant to tasks that depend heavily on one core. Neither result guarantees that every app will feel faster by the same amount.

The scores overlap or trade places

A small difference may be normal run-to-run variation. Browser activity, heat, power limits, and other tasks can change a score slightly. If one plan wins a run but loses the next, treat the results as roughly tied rather than picking the best-looking result.

One plan has lower scores after several runs

The computer may be limiting processor speed to save power, or it may be warming up during the test. Check that the test conditions are matched and repeat after the computer has cooled. A lower score alone does not prove a fault, and the test cannot identify the exact power limit or processor temperature.

The score is low in both plans

That does not necessarily mean the computer is slow or damaged. The score is a browser-based comparison, and results depend on the processor, browser, operating system, and current workload. Compare the two plans on this same computer rather than treating the score as a universal ranking.

How to make the comparison fair

1. Use the same power source. A laptop may behave differently on battery than it does while charging. Keep it plugged in for every run, or keep it unplugged for every run. Do not compare one plan on battery with another on AC power.
2. Set the power mode deliberately. In Windows 11, open Settings › System › Power & battery › Power mode and choose the mode you want to test. Some computers show different choices depending on their hardware or manufacturer software. On a Mac laptop, check System Settings › Battery › Energy Mode, if that option is available. High Power Mode appears only on supported Macs.
3. Keep other work quiet. Close apps that are rendering video, installing updates, syncing large files, or running another benchmark. A background task can use processor time and lower the score even when you did not start it intentionally.
4. Allow time for heat to settle. A processor can slow down when it gets hot. Use the computer on a hard, open surface, keep vents clear, and let it cool between runs. Avoid running a long series of tests back to back.
5. Keep the browser setup unchanged. Use the same browser and window for both plans. Pause browser updates and avoid opening extra tabs during the comparison. Extensions or a busy background tab can add work or interfere with a test.
6. Compare repeated results, not a single peak. Look at the pattern across three or more runs in each plan. If the difference is smaller than the spread within each group, the test has not shown a clear advantage.

Why power plans may not change the score much

A power plan is a set of choices about performance and energy use, not a fixed processor speed. The computer can still adjust its speed based on temperature, battery state, workload, and manufacturer limits. Some systems also apply their own performance controls in addition to the operating system setting.

The Processor Test reports performance in the browser, not the exact clock speed or temperature of the CPU. It can help you compare two settings on the same machine, but it cannot tell you which hidden power limit changed. If the results are close, use the mode that gives you the battery life and responsiveness you need, rather than treating a small score difference as a meaningful upgrade.