plot question

[William Blum]

Hello

I am a new user of Octave, version 2.19.15.  I choose to install the 
jhandles graphics backend because plots seemed to be significantly 
faster than the GNU plot option.  Is this still true with version 3.0?  
Also how does one switch between the 2 plot options?  If I download 
version 3.0 will it install over 2.19.15 or do I have to unintall 
2.19.15 first?  I am using Windows Vista operating system and obtained 
the previous Octave version from Octave Forge.

Thanks for your help.