If you play around with settings, I'd expect a near 60FPS experience a lot of the time.
As the action heats up, you'll see dips no doubt.... but I'd expect >40FPS most of the time, averaging 60FPS or a little higher at high(ish) settings.
Your 8GB of RAM could be a concern at high/Ultra settings. I've seen reports of 1080p/Ultra using a little more than 8GB itself!