there have been issues with Optifine and Tinkers construct in the past, its remove one of other on some of the mod packs i've played.
there was a whole raft of comments about Opti & TC
might try :
The Optifine mod appears to have issues with Tinker's Construct:
1. Many times certain body parts like limbs or heads go missing/invisible.
This occurs on all mobs, as well as player characters.
The fix for me was to set Chunk loading from multicore to default.
see if it helps not sure it will though.
as of Tinker Construct 1.5.0 a no in the change log shows :
"Added a warning message to crashlogs regarding GregTech or OptiFine(We don't support these mods in any way)"
some recomendatiosn suggest :
http://www.minecraftforum.net/forum...hanted-item-lag-fix-more-fpsplus-1-5-2-1-7-10
as an alternative to optifine, but i've not used it my self.