I know it's not the resource pack, I also know it's not the Direwolf20 pack, but separately it's not the added mods to the pack, so what could it be?!
Signs You're an Aging Gamer: You Press the "A" or "X" Button Rapidly During Loading Screens
How old are the graphics drivers on your PC?
"We live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far."
I've updated them multiple times in the current year... they should be fully updated...
What version of Minecraft