I doubt that you have software that will protect you against buffer
overflow. DEP does not allow data that follows a buffer overflow event to
execute in memory space, thereby preventing possible serious damage to your
data. DEP does not slow down your computer. DEP does not affect the
behavior of any programs. DEP does not take up any of your RAM or swap
file.
While you can disable DEP, there would be no gain in doing so...in fact you
expose your machine to vulnerabilities that cannot be effectively stopped by
software on a real time basis.
My advice is to leave it enabled.
Bobby