I was incorrect...it is 24GB of Ram and it does max out, even after making adjustments in PS CC Preferences.
Another point is, when Canon introduces a high MP FF body, I'm gonna get one. I can only assume that stacking
35MP images will be more memory intensive than the current 22MP images...right?
I have been using Zerene for about 3 weeks on my floral stuff and found that it does do a great job, except...it does introduce unacceptable noise.
Prior to that, PS CC was my weapon of choice, albeit, a lot of artifacts. Then it quit stacking at all.
But PS CC upgraded last week...the stacking works much better than before with virtually no artifacts.
As a side note, I took a stack from PP CC and Zerene and stacked them together...looked good.