Modify the tuning settings of your AV/AS policy:
- Open the SEPM Console
- In the Policies tab, under Antivirus and Antispyware, select the policy, right-click and choose Edit..
- In the left pane, under Windows Settings, choose Administrator-Defined Scans
- In the right pane, select the Scheduled Scan you wish to modify and click Edit..
- Under the Scan Details tab, click Advanced Scanning Options..
- Under the Tuning tab, drag the slider to 'Best Application Performance.' (The description for this setting is 'Optimized to run other applications as fast as possible' and 'The scan may run slower.')
Is this the setting you were looking for?