glitch I do not know how to describe it, but recently my minecraft behaves strangely, here are the screenshots. (if the time glitch to make a screenshot in the game, then the game crashes because of what I had to do a screenshot with the buttons)
MC-167322
Glitch
Resolved
Cannot Reproduce
0
Update your graphics driver to latest 441.41 and see if the issue persists.
For your GT640 you can d/l it from here: https://www.nvidia.de/Download/driverResults.aspx/155101/
Edit: according to what can be seen on the screenshots, it rather looks like your gpu is going to die real soon. Could also be defective vram. Do you play other games than Minecraft?