If you're running on Nvidia drivers, please try the following steps to see if it improves your issue:
- Right-click on your desktop
- Open Nvidia Control Panel
- Click 'Manage 3D settings'
- Select 'Program Settings'
- From the 'Select a program to customise, click the dropdown and select 18 Football Manager (FM.exe)
- Click on this to select it
- Now within the options, scroll down to where it says 'Vertical Sync'
- Click on it and select 'Fast'
- Click 'Apply'