For linux you need to install the manufacturers driver to get decent 3D acceleration. Fortunately the nvidia linux drivers are rather good. You've essentially got two choice's let ubuntu do it for you (and trail a bit behind in terms of driver development) or download the linux driver from NVIDIA http://www.geforce.com/drivers/results/52240 and install it yourself (currently version 310.91).  Downloading and installing the driver yourself is straightforward enough, but best to find a linux geek to run through it the first time.

I doubt it massimo got it about right, see  https://forum.processing.org/topic/processing-2-0-won-t-run-on-netbooks-and-older-cheaper-hardware.