I think doing them in the background after loading up your character is just about the right time to do it (at least if done correctly). If they manage to properly thread the calculation process then game performance should not suffer in any noticeable way. If, on the other hand, the calculation is postponed to when the dialog is actually opened you might need to wait for a very long time before you can actually use the dialog. Let's assume you have a five minute load time now and 1 minute after the patch, then I would assume you'd need about 4 minutes to do the calculations... That's four minutes looking at an unresponsive UI and if there's one thing that freaks me out it's having to look at an unresponsive UI. (Yes, I hate the game-freeze you get when toggling between completed/active quests).
Originally Posted by banjolier
Doing it during log-in is obviously too early.
Doing it when opening the dialog is too late.
Doing it somewhere in between in a manner that do not reduce game performance is when it should be done.
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