DotarSojat

I started playing Tekkit Classic a few days back and was experiencing the same exact thing that you were in the pictures you posted. I uninstalled and reinstalled the technic launcher like 4 times and tried different versions of optifine and etc with no luck for 2 days. It was really getting under my skin because nothing I tried helped at all. It actually wasn't until I googled it that I came across this thread that had not solution to the fix that I soon after realized that it was a graphic option that was enabled in the NVIDIA control panel lol. Idk how I thought of it or remembered the description from the optifine page but thank god I did because I was about to give up and not play at lol! If you have any questions or need further assistance fixing this problem let me know and I will help the best I can because I know first hand how annoying that graphic problem is!

I was having the same problem and for days couldn't figure out how to fix the problem for the life of me. I then remembered a while back when I installed optifine into original MC and not Tekkit that in the instructions it mentions going to your NVIDIA control panel and disabling/turning off "Threaded Optimization"/"OpenGL Threading". here is a direct quote from their actual page below. "The option "Video Settings -> Chunk Loading" switches between Standard, Smooth and Multi-Core chunk loading. When using "Chunk Loading: Multi-Core" make sure to Disable "Threaded Optimization" / "OpenGL Threading" in the graphics card control panel (example). For best results disable it globally, not only for java.exe or minecraft.exe." You can access the control panel by right clicking desktop or going to start and typing in "NVIDIA control panel". On the left side under "Global Settings" is where you will find the option in the list. This will fix the graphical problem that you have been having.