In previous betas, even on very large and crowded galaxies my performance has been incredibly smooth. 6.2 has been a great step backward; FPS has dropped when fully zoomed out, time between turns has increased (and there have been some "Wait" hangs that never ended), and the overall experience has been diminished.
System specs:
i7 4930k, 4.1ghz
64GB DDR3
Geforce 770 GTX 4GB
Dunno if the memory leak fixes might have gone hinky, but whatever it is, something's definitely gone wrong.