Hello,
I think that the first thing to do is plan the processing. You will not be able to put 640,000 pictures in the software and expect something to come out.
How are pictures organized ? What is this exactly ?
The main idea on big projects is to align small overlapping clusters seperately and then align clusters together, and clusters of clusters until you have the alignment output you need… And this require precise planning. You can do this manually and/or with the CLI.
Still 640,000 is quite a high number of pictures !