Hello,
I downloaded the 1.7 beta and started a game, and it ran great. It was a small map with 1 opponent, which is something I couldn't do before because of the memory problems.

However, If I play the game on a large map, with 5 opponents, with the terrain slider at 0%, and "enhance ship textures" off, I still eventually get a crash. I loaded a save, which luckily was the turn before the crash, and it crashed immediately upon loading. The ram usage was at about 2gb both times.

I started a new game, and cheated to make sure I wasn't conquered, and then just hit "turn" over and over again until the game crashed. I noticed that it crashes after a battle, or to be more specific, when 1 opponent attacked another in my sensor range. This might have just been the straw that pushed the limit, but still. I'm going to try a game with No mods what-so-ever, and 1 with my preferred mods, and see the difference.

I did notice a large increase in performance when I have visual mods loaded. Before (1.61) if I ran a large map, with 5 custom races (using the Star Wars, Babylon 5, and Star Trek ship models), the game would last 12 turns (the 2nd autosave), now it runs much longer than that, but I haven't tested it fully. So great job so far.

I can post the debug file of my next game if it's wanted. This comp is winXP sp2, 2gb Ram, 4gb pagefile, radeon 1900xt 512mb video card.