Melter

The drop is determined when you kill the monster, otherwise the ring of wealth could not affect any monster drops at all. I do agree 100% that the drop is not completley random as computers cannot generate truly random numbers (rather, the random number generator function in java probably takes some element such as the current time from the system clock and uses a mathematical formula to derive a number from it). That said, I disagree that you can predict when a rare drop will occur at all. It doesnt make sense that jagex would put some counter into the game when simply choosing a random number from various ranges of numbers (depending on rarity of the item) to determine the drop would be more simple and more random. Even if there was a counter - jagex stores so much information on their servers, im sure they could store the last recorded number in the counter before a system update, or simply reset it to 0. If your drop rate was indeed 65% after a system update, im sure youre onto something regarding the chance of getting a rare drop, but I doubt it has anything to do with some counter.