I'm quite the noob to Ubuntu and I tried it a long time ago and had this problem, and after reinstalling today i'm still having it. I duel boot alongside Windows 10 which runs perfect, but on Ubuntu it's absolute trash. I can't watch a youtube video without freezing and lagging, and even the menu for lubuntu lags. Yes, obviously I updated my Nvidia drivers in the additional drivers so please do not suggest that. Can anyone possibly give me some help? Thank you!
Specs:
Ubuntu 16.04
Memory: 24 GB
Processor: Intel(R) Core(TM) i7-6700 CP
Graphics: NVidia GeForce GTX 745
OS Type: 64-bit
Best Answer
NVIDIA has always been problematic. I understand that, you have already updated the drivers, but here is another process of doing it:
sudo apt-add-repository ppa:xorg-edgers/ppa && sudo apt-get update && sudo apt-get install nvidia-current nvidia-settings