I just put ABH like 7 years ago after some new things, and my game lags like no tommorow
REvenger The number of parts alone causes a lag due to the game's management of the part list. Since around 0.15.x buffs causes more lag than before due to whatever new checking logic. So it depends on your computer, the size of the ship, the size of the crew and how or what you are building using what parts.
REvenger If you are using the same pc/laptop as 7 years ago, then that's your problem.
Is your computer old? Because ABH is a heavily mod with alot of content. And if not, you should provide logs so that other people can help.
(PS: Sorry but I might not be able to help)
Roasted iness laptop, prob 15 years old or 10, refurbished
REvenger Yea, your thing is too old mate.
