Game running in slow motion

I recently bought the game on sale and it isn't running properly. The game ran fine when I played the beta but now if I play arcade the game runs in slow motion a couple of seconds after the start of the match, pretty much as soon as any troops appear on screen. Even when I play online my character moves more slowly than my team. I meet the recommended requirements and changing graphical settings makes no difference. Frame rate seems to still be 60 but just running slowly.