The animation of each engine as well as the sound of them chugging is what caused most of the lag. I found putting a sound muffler by the engines made the game smoother when in the area. TE dynamos don't move or make noise. I was amazed using opis in the newest packs and seeing how little effort TE machines put on your pc. A chunk with a a couple chickens and and about 10 eggs on the ground was causing about 100 times more tick lag than a bunch of running TE machines.In 1.6.4 packs, TE Steam Dynamos instead of ISEs on top of the boilers seems to run pretty smooth with no lag. Seems to be the engines rather then the boilers that were the source of most of the fps/lag issues.