Just to clarify, we aren't making any changes to the chance that an item will drop. Instead, we're changing the quality of that item when it drops. And when we say we're increasing the likelihood that non-Elite monsters will drop magical items "by a factor of four," it means that those monsters should drop 4 times (or "4x") the amount of magical items as they do now. It's important to note, however, that this will only affect Magic items and Rare items.

So, for example, if doing a full clear of an area currently yields 500 items from non-Elites, it will still yield 500 items after 1.0.4. Whereas you may have only gotten 20 Magic (blue) items and 4 Rare (yellow) item from those non-Elites before, you'll now get approximately 80 Magic items and 16 Rares.