Mine Follies

[MoonDragn]

Try the boarding ships I mentioned, start taking over his colony ships and colonize your unused planets in your systems... move their population around to your planets that can use them, I usually pool them on a planet with the right atmosphere til they are large enough to have be productive on their own.
Abandon your undefendable positions... I usually try to keep down the number of warp points into my systems. Start building the star destroying ships if you have the tech, It will make a difference if you blow up the system adjacent to you with the computer, he would have a longer supply line
I usually stop my empire near black holes too, that seem to slow the computer down alot