After buying a second hand imac 20" (late 2006 model) I keep reading a lot of things about them only lasting 3 to 5 years? Although im not sure if this is the g5 model? Althugh I thought they were the same thing? how long are they expected to last, roughly? I guess theres no way to tell when it was first purchased but obviously must be late 2006 or after for mine. Its a core duo 2, so are these better reliability wise than the g5 I wonder. thanks!