When does the sort memory usage come into play?

I have SortMemUpperLimit = 67108864 in my configuration, but my memory
usage never goes above my DefaultDbCachePages settings.

I expected the max memory usage to be (DefaultDbCachePages * Page
Size) + SortMemUpperLimit when a SORT is involved. But I'm not seeing
it, so I'm assuming my understanding of SortMemUperLimit is incorrect.

So, like I said, When does the sort memory usage come into play?


Thanks