Why is moving from Win 7/ Access 2007 to Win 10/Access 2016 on a faster PC 15x slower?

My Access development HP Probook 4540s laptop has been a lowest common denominator 64-bit Win 7 running Office 2007 on an i5-3320M @ 2.60G with 8G RAM and a zippy SSD drive replacement. The only client I now support with this unit requires a lengthy Access single form app that runs pages of a tons-of-math VBA translation of an elderly FORTRAN simulation now tied to more modern databases, reporting, Internet access, etc. The application runs a setup, an iteration main section for each team, and a dump of reports to PDFs. This takes about 4 seconds. Even before I popped the SSD in, it never required more than about 20 seconds.

My client bought a new Dell with Win 10 running Office 2016 on an i7-7760(?) @ 2.90 with 16G RAM and whatever default hard drive and it requires a minimum of 1 to 1 1/4 minutes, sometimes longer. It never hangs, however, during each team iteration, I throw progress info to the screen and after team 2 or 3 displays, he'll usually, but not always, get a "Not responding" up top. The screen ceases to update until the app has run its course.

No one is going to get old waiting less than two minutes for a final product run, but during development/testing, we might run the app dozens of times in an hour and it is a pain.

Are there optimizations we can perform to resolve this?

Thanks,

Marc