Today, not much differentiates them. But as time passes our only option will be to further specialize the hardware to get realistic gains; at some point perhaps a 'purpose built analog' computer kinda thing will get to the point where it is so useful, that it would be like the 'Standard Template Constructs' concept in Warhammer 30k. So what you can make a faster ai but, the current one can 'teach everyone, basically anything'.