This latest patch does a lot of tinkering under the hood of StarDrive. You should see substantially better performance memory-wise and in the late game. You should also see much better play out of the AI due to economic tweaks. Their Core Strategic AI remains unchanged - it should be quite tricky as is. But now their Economic AI is much better, which means they will have more ships and better ships to fight you with. I took a long look at what type of things players were doing to get good economies and also at where the AI was making dumb economic choices. Let me know how your conquest goes!

Added fairly major memory optimizations. Possibly eliminated OOM errors. Please let me know your results
Added the Kulrathi Titan
Added Vulfar Titan
Changed the peace treaty notification icon to a dove icon
Double clicking a planet will no longer explore it automatically
Ships with ordnance fabricators will no longer be the target of resupply shuttles
EMP Torpedoes now actually do EMP Damage!
Added an indicator on the planet list screen for systems that have a known enemy presence
The cancel colonize order button on the planet list will properly abort the mission of a colony ship en route
Fixed an error where Cybernetic governors were not considering the effects of the tax rate in deciding how to set their production labor allocations, which could lead to poor results and starvation.
The Cybernetic AI will no longer colonize planets which have less than 1.0 richness
The Cybernetic governor will build biospheres on the best planets
Core World governors will now build biospheres automatically if they determine that it is beneficial to do so
Added new Core / Research world governor behavior which will adjust production and research percentages to try and make a profit when running at a deficit
Drastically changes the weight the AI gives to making capital ships (want them to build lots more)
Reduced the number of freighters and passenger transports the AI wants to build
The AI will be smarter about building up its fleet so as to keep its economy running smoothly
The AI will now be more aggressive about scouting
Governors will be more careful about building shipyards unless they can be properly supported financially
All governors will be more careful to only begin construction projects when they believe they can afford the maintenance
The AI will build projectors only if they can very comfortable afford them
Changed a Core World governor rule that would have them switch to research if their production stores get full. Won't do that anymore because it affects their taxes
Changed the way ship maintenance works. Maintenance is now a fixed amount depending on ship class.
Fixed an error where the Ship Scrapping logic would collide with the Auto Explore logic to have stuttery-looking AI scout ships
Fixed an error where expeditionary fleets could run out of ammo and fail to rearm