Adjust the sampling rate in reports
Change the sampling size to adjust report accuracy and speed.
When you view a sampled report, you have the option to adjust the sampling rate in order to increase accuracy and affect how quickly the report loads.
Click the dropdown menu at the end of the menu bar. Select an option. Your data automatically refreshes using the new setting. Your preference is saved across all of your reports, but resets after you close Google Analytics. You can change this at any time.
Producing unsampled reports requires a huge processing load, so the adjustments you can make to sampling rate is limited. Learn more about sampled data