I have the same issue only in single player and with my geothermal generators, Whenever they are producing power actively and I move away I start to get extreme FPS lag and only a full mc restart will fix it.
*Edit*Quick test showed me it is indeed related to sound, when I put the slider to "off" there is no noticable lag when going to my cacti farm or mining field (wich usually is an enormous stutter of 5 fps till I restart MC) At least for me this is the case.
thanks for your answers on the subject, helped to clear up a few things.
A bit hesitant to move anything now but that will work out 
Good day
basicly what the title states, when I wrenched my newly installed mass fab to relocate it I got back a advanced machine. Was kinda frustrated at the loss, made a new one 2 hours later and backed up my save, wrenched it again and it just popped off nicely. So I rebuild my installation it worked fine and i got the the point to upgrade it again and had to relocate. I made sure everything was out of the mass fabricator and it again yielded a advanced machine block rather then a mass fab. The only difference between this and the time it worked properly was that it had power in the "lighting bolt" slot.
Is this a "feature" or a bug ?
*i googled, i searched this forum, couldn't find anything concering this issue
