I have a saved game in which there are so many ships and other objects that on my Quad-SLI nVidia 7950 I only get 3 frames per second using 1.6 beta 2.

But in the current internal build, scheduled to go up later this week we hope, we're seeing 30+ frames per second. A 10X performance improvement.

How? Even though 1.6 is a "point release", we have back ported part of the new graphics engine from the upcoming fantasy strategy game that is in development. Mind you, only a piece of it, but enough to make a huge performance improvement.

I am just incredibly excited to find out how people react to the speed difference here. It should make a massive difference for players playing on all sizes of galaxy. 

1.6 has slowly turned into the performance tuning release.  1.6 beta 1,2,3 included new features but they've seen things such as the mini map and graphs rewritten in Direct3D to help performance on Windows Vista (which also helped all users too since it is faster). 

We will definitely be looking to find out how much of a change people notice with this next beta.  Hopefully beta 2 and 3 that are up (1.59.095) have shown significant improvements. The next update will be the biggest yet.