I have done some testing this morning with various settings, and I have narrowed down the performance issues to two main things:
1. Time & sales is very intensive, removing it speeds up performance.
2. Even more importantly, range charts are also very intensive... even without any indicators, a range chart seems to slow things down significantly. With a few range charts open the time and sales coming in lags in a noticeable manner.
Apparently NY7 has a number of performance improvements - hopefully we will get to see them soon!