If you've launched the game and your graphics star rating within preferences is lower than you expected, or the graphics quality is set lower than you think we suggest the following.
First, exit the game. Make sure that if you're running via a laptop that it's connected to the mains and isn't running in Power Saving mode. You can check this via you Control Panel\All Control Panel Items\Power Options. This is also worth checking regarding power saving on a desktop.
Once you've checked this, delete your cache and preferences folders.
Once you've done so, relaunch the game. You may find it takes a little longer to load up as it will re-benchmark your system to make sure the settings are correct.
If you find even after doing the above your star and/or graphics settings are low, try playing a match with the graphics set to what you would expect them to be and see how the game performs.
If you're still finding you're having issues, it may be your anti-virus program interfering with the game and/or the launching platform, so please read and follow our FAQ instructions on how to configure this.