If I swap out the NVRAM cartridge on a MICS XC7.0 with another cartridge that I've changed the capacitor in, will I loose programming on the system?

There are several expansion modules, an analog DID card and over a hundred phones. I really don't want to loose it. I will backup with a rad. Perhaps the only way to do this is to swap, then restore? 2nd question: about how long should a backup take to run? I want to be sure it's really backing up and not failing.

Thanks!
Jim