Step 1: Go to Control panel - Power options
Step 2: Now click on the "Change plan settings" next to the selected power plan.
Step 3: Click on "Change advanced power settings".
Step 4: Now, expand the "Graphics settings".
Step 5: Make sure the "Maximum performance" is selected on both battery & plugged in options.
Step 6: Apply the settings, restart your notebook and then check the performance.
Step 7: I would also recommend you to check the other settings under the advanced power options settings if the issue still persists.
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