See, now this is precisely why I became a CS professor: so that if anyone asked, I could give not merely my opinion, but my professional, expert opinion, on the question of whether psychopathic Terminators will kill us all.
My response (slightly edited) is below.
I fear that your question presupposes way too much anthropomorphizing of an AI machine—that is, imagining that it would even be understandable in terms of human categories like “empathetic” versus “psychopathic.” Sure, an AI might be understandable in those sorts of terms, but only if it had been programmed to act like a human. In that case, though, I personally find it no easier or harder to imagine an “empathetic” humanoid robot than a “psychopathic” robot! (If you want a rich imagining of “empathetic robots” in science fiction, of course you need look no further than Isaac Asimov.)
On the other hand, I personally also think it’s possible –even likely—that an AI would pursue its goals (whatever they happened to be) in a way so different from what humans are used to that the AI couldn’t be usefully compared to any particular type of human, even a human psychopath. To drive home this point, the AI visionary Eliezer Yudkowsky likes to use the example of the “paperclip maximizer.” This is an AI whose programming would cause it to use its unimaginably-vast intelligence in the service of one goal only: namely, converting as much matter as it possibly can into paperclips!
Now, if such an AI were created, it would indeed likely spell doom for humanity, since the AI would think nothing of destroying the entire Earth to get more iron for paperclips. But terrible though it was, would you really want to describe such an entity as a “psychopath,” any more than you’d describe (say) a nuclear weapon as a “psychopath”? The word “psychopath” connotes some sort of deviation from the human norm, but human norms were never applicable to the paperclip maximizer in the first place … all that was ever relevant was the paperclip norm!
Motivated by these sorts of observations, Yudkowsky has thought and written a great deal about how the question of how to create a “friendly AI,” by which he means one that would use its vast intelligence to improve human welfare, instead of maximizing some arbitrary other objective like the total number of paperclips in existence that might be at odds with our welfare. While I don’t always agree with him—for example, I don’t think AI has a single “key,” and I certainly don’t think such a key will be discovered anytime soon—I’m sure you’d find his writings at yudkowsky.net, lesswrong.com, and overcomingbias.com to be of interest to you.
I should mention, in passing, that “parallel programming” has nothing at all to do with your other (fun) questions. You could perfectly well have a murderous robot with parallel programming, or a kind, loving robot with serial programming only.
Hope that helps,