I can not say about previous versions, but now it's very problematic to play with gregtech, you can say it's almost impossible.
1. Graphical bug (although it is written that corrected in the Dev version) already makes the game not tolerable, but with OptiFine it just increases many times.
2. The overall performance of the mod is not allowed for a protracted game (I just put in a flat world only 100 wires / pipes and my fps fell from 60 to 9)
That is to return the mod to life you need to do this. Although it's not clear to me, 901 the error ticket is already hanging like half a year, but this serious problem is not solved, it seems to me or the development was abandoned?
But the mod is good. Thanks to the developers for it.