What's the hardest (longest-running) financial calculation?

[EdS2]

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I was idly wondering: which of the many functions and features of a financial calculator will take the longest time to run? (In my case it would be run on an HP30b but the various HP-12C models would be an obvious choice of machine.)

(I suppose it might be that the 30b can tackle some calculations more efficiently than the 12C. It just possibly might be that in some cases it is less efficient.)

With ref to this recent benchmarking thread:
12C Platinum vs. 48GX vs. 50g (Speed Test)