That's quite true. I mean, honestly, I would expect any AI to parallelize very well, although I'm loathe to trust my intuition about anything related to AGI. But I don't think we can take it as a given that the AI will be able to get linear or better gains in its speed of thought when going, say, from some big parallel supercomputer in a datacenter to trying to spread itself out through commodity hardware in other physical locations.

If a prospective AI had a tremendous, planet-sized amount of hardware available to it, it might hardly matter, but in the real world, I imagine that the AI would have to work hard to obtain a sizable amount of physical resources, and how well it can use those resources could make the difference between hours, days, weeks, or months of "FOOMing."

EDIT on reflection: Yeah, maybe I'm underestimating how many resources would be available.