If you've had a single simulation take a week to finish, then you have already used up 1% of your development time for 2 years.

Good point. I tend to discount long chunks of CPU time because I usually overlap them with personal mini-vacations =P. Thinking about it in more detail I probably spend about 10% of my time waiting for simulations to finish.

But even using your 1% number, the speedup would be 100x, not 1,000x.

Disregarding doing multiple tests/simulations/compilations at once.

I work in video games, specifically via cloud computing, and waiting on various computer tasks can easily take up 10%-30% of my time per day.

I do game dev on the side. The projects are much larger than my scientific projects and allow for much more room for parallel development. If I were a mind running at 1,000,000 times speed I would branch my project into a hundred different miniprojects (my todo list for my current game has well over a 100 well separated items that would merge well). I would write the code for all of them and then compile them all in a giant batch in parallel. This would give me a 100 fold speed up, on top of the 10 fold speed up, giving me a 1000 fold speed up in total. I won't claim that this would be a comfortable way to code, but it could be done.

My larger point was that the effective speedup across the space of tasks/fields is highly uneven and a superfast thinker would get the most utility out of low-computational occupations that involve abstract thinking, such as writing.

50 years ago computers were much, much slower, but human minds were just as fast as they are today. Was it optimal back then to be a writer rather than a programmer? (Edit: This is a bit of a straw man, but I think it still shines some light on the issue at hand)