Thanks, Andrew, yes raw files. But I also checked an old D800 NEF and it goes from 44 MB to 207 MB when opened in PS. There must be a reference on this somewhere, eh?
Did some math. D800 NEF 7360 x 5912 pixels at 16 bits per pixel is 696,197,120 bits. Convert to 8-bit bytes and I get 87,024,640 bytes or just under 85 MB. Can there be over 100 MB of extra info when rendered?
PS I do use lossless compression, but that shouldn't alter my math assumptions. But you know what they say about assume...
I also realize that I am saving 14-bit NEF to the card.