Weekdays, eastern time, its fine until like 4-5PM, toward the end, its palpable slightly, to some people. By 8 its generally not what most would call 'playable'. It ends, depending on when the ball groups, if there were any on, between 11pm and 2am. Adjust for PST, so, +3 hours? Really it just depends if there are ball groups on. The whole server can feel when they start doing whatever the heck it is they do to the API.