Is Loot determined when the moster dies?

Loot is generated upon creation.

As soon as you step into an instance, or a mob is created in the world, the loot that's going to drop has already been determined.

Q u o t e:
What are the variables in the random generator's kernel, is it based on some attribute of the players in the raid, or the raid leader?

Heh, no.

I believe it uses a time stamp to seed the generator. So, there's nothing you can influence within the game that would alter or coerce the generator.

Q u o t e:


So what you are saying is that we've killed Curator at the exact same second each week for the last 7 weeks, to account for the Champion gear? Or 14 out of the last 15 weeks? All we have to do is kill him a minute later? Huh...

No, the time it uses to seed would have no real implication into the final outcome of what loot its given. On a long enough generation table, you may see some type of pattern based purely on a random generators inability to truly be random. But we're talking about astronomical numbers, something ridiculous like hundreds of billions of generations. Nothing you would or could see a pattern in during your time playing the game.

What you're seeing is pure and basic laws of probability. Have a few thousand people roll a pair of dice and you're bound to see hundreds of people able to roll snake-eyes 10 times in a row. (not that dice are truly random either)

Q u o t e:
I believe loot is determined at the time the mob dies. How else would quest mobs drop quest items for people only on the quest? Does it register client side or is the quest item in the spawn only for people who are on the quest?

Quest items are always there, they're just hidden if you don't have the quest.

Q u o t e:
Thanks Drysc for posting this up. This has been unclear to the wow community for a very long time and many wondered. Thanks!

Well hopefully I'm still here tomorrow then, I didn't realize it wasn't common knowledge or at least discussed officially before.

edit: Sorry, a lot of people took that a bit too seriously. I'm not going anywhere, we don't dangle that precariously on the precipice of ultimate job security. Too much humanity here for that. :) Just an attempt at humor.

Q u o t e:


After stepping out of an instance or logging into an empty zone, I've often seen all the mobs throw up their buffs at the same time. Is this just my client, or does the server only create the mobs when someone's around to reduce load?

The mobs aren't actually created until someone enters the area. Sometimes you'll see mobs sort of "fall" a bit to the ground, or groups of mobs all fan out from a single point. This is usually the creation happening. Ideally you don't notice it at all though.